Digital broadcasting system and method of processing data in the digital broadcasting system

ABSTRACT

A broadcast transmitter and a method of processing broadcast data in the broadcast transmitter are disclosed. The method includes the steps of performing RS encoding and CRC encoding on mobile service data to build RS frames belonging to an ensemble, wherein each of the RS frames are mapped into data groups, wherein each of the data groups comprises known data sequences and a portion of FIC data including information for rapid mobile service acquisition, wherein the information for rapid mobile service acquisition includes transport stream identification information for identifying a mobile broadcast carrying a mobile service that includes the mobile service data and C/N indication information for indicating whether the FIC data are applicable to a current transmission frame or a next transmission frame, multiplexing data in the data groups and main service data, and transmitting a transmission frame including the multiplexed data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/197,972, filed on Aug. 25, 2008, now U.S. Pat. No. 8,059,210, whichclaims the benefit of and right of priority to U.S. ProvisionalApplication No. 60/957,714, filed on Aug. 24, 2007, U.S. ProvisionalApplication No. 60/974,084, filed on Sep. 21, 2007, U.S. ProvisionalApplication No. 60/977,379, filed on Oct. 4, 2007, U.S. ProvisionalApplication No. 61/044,504, filed on Apr. 13, 2008, U.S. ProvisionalApplication No. 61/076,686, filed on Jun. 29, 2008, and KoreanApplication No. 10- 2008- 0082428, filed on Aug. 22, 2008, the contentsof all of which are hereby incorporated by reference in theirentireties.

BACKGROUND OF THE INVENTION

1. The Field

The present invention relates to a digital broadcasting system and amethod of processing data in a digital broadcasting system fortransmitting and receiving digital broadcast signals.

2. Discussion of the Related Art

The Vestigial Sideband (VSB) transmission mode, which is adopted as thestandard for digital broadcasting in North America and the Republic ofKorea, is a system using a single carrier method. Therefore, thereceiving performance of the receiving system may be deteriorated in apoor channel environment. Particularly, since resistance to changes inchannels and noise is more highly required when using portable and/ormobile broadcast receivers, the receiving performance may be even moredeteriorated when transmitting mobile service data by the VSBtransmission mode.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a digitalbroadcasting system and a data processing method that are highlyresistant to channel changes and noise.

Another object of the present invention is to provide a receiving systemthat can provide both main and mobile services and to provide a dataprocessing method of the receiving system that can automatically switchto any one of the main service and the mobile service based upon thereceiving environment (or condition) of the receiving system.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, areceiving system includes a receiving unit, a signaling decoder, an SIhandler, a main service data processor, a mobile service data processor,a controller, and an output controller. The receiving unit receivesmobile service data and main service data including the same A/Vbroadcast signal and receives retransmission channel information.Herein, the mobile service data configures a data group, the data groupincludes a signaling information region within some of the multiple datagroup regions, and the signaling information region includestransmission parameter channel (TPC) signaling data and fast informationchannel (FIC) signaling data. The signaling decoder detects the fastinformation channel (FIC) signaling data from the received mobileservice data. The SI handler acquires channel configuration information(or a service map table (SMT)) of the received mobile service data usingthe detected fast information channel (FIC) signaling data. The mainservice data processor performs demodulation and error-correction on themain service data received by the receiving unit and temporarily storesthe processed data. The mobile service data processor performsdemodulation and error-correction on the mobile service data received bythe receiving unit and temporarily stores the processed data.

The controller generates a control signal based upon the retransmissionchannel information received by the receiving unit and a receivingenvironment of the receiving system and outputs the generated controlsignal. And, the output controller selects any one of the A/V broadcastsignal for the main service of the main service data processor and theA/V broadcast signal for the mobile service of the mobile service dataprocessor based upon the control signal of the controller.

The retransmission channel information may include at least one ofretransmission identification information for identifying aretransmission status of the main service data, channel information onthe retransmitted main service data, interval identification informationidentifying whether the mobile service is faster or whether the mainservice is faster, and interval information between the mobile serviceand the main service.

And, the retransmission channel information may be included in at leastone of the FIC signaling data and the SMT and received.

In another aspect of the present invention, a data processing method ofa receiving system includes the steps of receiving mobile service dataand main service data including the same A/V broadcast signal andreceiving retransmission channel information, wherein the mobile servicedata configures a data group, wherein the data group includes asignaling information region within some of the multiple data groupregions, and wherein the signaling information region includestransmission parameter channel (TPC) signaling data and fast informationchannel (FIC) signaling data, detecting the fast information channel(FIC) signaling data from the received mobile service data, acquiringchannel configuration information (or a service map table (SMT)) of thereceived mobile service data using the detected fast information channel(FIC) signaling data, performing demodulation and error-correction onthe received main service data and temporarily storing the processeddata, performing demodulation and error-correction on the receivedmobile service data and temporarily storing the processed data, andreferring to the received retransmission channel information and areceiving environment of the receiving system, thereby selecting andoutputting any one of the temporarily stored main service data andmobile service data.

Additional advantages, objects, and features of the invention may berealized and attained by the structure particularly pointed out in thewritten description as well as the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram showing a general structure of adigital broadcasting receiving system according to an embodiment of thepresent invention;

FIG. 2 illustrates an exemplary structure of a data group according tothe present invention;

FIG. 3 illustrates an RS frame according to an embodiment of the presentinvention;

FIG. 4 illustrates an example of an MH frame structure for transmittingand receiving mobile service data according to the present invention;

FIG. 5 illustrates an example of a general VSB frame structure;

FIG. 6 illustrates a example of mapping positions of the first 4 slotsof a sub-frame in a spatial area with respect to a VSB frame;

FIG. 7 illustrates a example of mapping positions of the first 4 slotsof a sub-frame in a chronological (or time) area with respect to a VSBframe;

FIG. 8 illustrates an exemplary order of data groups being assigned toone of 5 sub-frames configuring an MH frame according to the presentinvention;

FIG. 9 illustrates an example of a single parade being assigned to an MHframe according to the present invention;

FIG. 10 illustrates an example of 3 parades being assigned to an MHframe according to the present invention;

FIG. 11 illustrates an example of the process of assigning 3 paradesshown in FIG. 10 being expanded to 5 sub-frames within an MH frame;

FIG. 12 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted;

FIG. 13 illustrates a hierarchical signaling structure according to anembodiment of the present invention;

FIG. 14 illustrates an exemplary FIC body format according to anembodiment of the present invention;

FIG. 15 illustrates an exemplary bit stream syntax structure withrespect to an FIC segment according to an embodiment of the presentinvention;

FIG. 16 illustrates an exemplary bit stream syntax structure withrespect to a payload of an FIC segment according to the presentinvention, when an FIC type field value is equal to ‘0’;

FIG. 17 illustrates an exemplary bit stream syntax structure of aservice map table according to the present invention;

FIG. 18 illustrates an exemplary bit stream syntax structure of an MHaudio descriptor according to the present invention;

FIG. 19 illustrates an exemplary bit stream syntax structure of an MHRTP payload type descriptor according to the present invention;

FIG. 20 illustrates an exemplary bit stream syntax structure of an MHcurrent event descriptor according to the present invention;

FIG. 21 illustrates an exemplary bit stream syntax structure of an MHnext event descriptor according to the present invention;

FIG. 22 illustrates an exemplary bit stream syntax structure of an MHsystem time descriptor according to the present invention;

FIG. 23 illustrates segmentation and encapsulation processes of aservice map table according to the present invention;

FIG. 24 illustrates a flow chart for accessing a virtual channel usingFIC and SMT according to the present invention;

FIG. 25 illustrates an exemplary bit stream syntax structure of an EMTaccording to another embodiment of the present invention;

FIG. 26 illustrates an exemplary syntax structure of an FIC segmentincluding retransmission channel information according to an embodimentof the present invention;

FIG. 27 illustrates an exemplary syntax structure of an SMT sectionincluding retransmission channel information in a field format accordingto an embodiment of the present invention;

FIG. 28 illustrates an exemplary syntax structure of an SMT sectionincluding retransmission channel information in a descriptor formataccording to an embodiment of the present invention;

FIG. 29 illustrates an exemplary syntax structure of a retransmissionchannel information table section according to an embodiment of thepresent invention;

FIG. 30 illustrates a flow chart showing process steps of a method forprocessing main service data and mobile service data according to anembodiment of the present invention; and

FIG. 31 illustrates a block view showing a structure of a receivingsystem according to another embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Hereinafter, the preferred embodiment of the present inventionwill be described with reference to the accompanying drawings. At thistime, it is to be understood that the following detailed description ofthe present invention illustrated in the drawings and described withreference to the drawings are exemplary and explanatory and technicalspirits of the present invention and main features and operation of thepresent invention will not be limited by the following detaileddescription.

Definition of the Terms Used in the Present Invention

Although general terms, which are widely used considering functions inthe present invention, have been selected in the present invention, theymay be changed depending on intention of those skilled in the art,practices, or new technology. Also, in specific case, the applicant mayoptionally select the terms. In this case, the meaning of the terms willbe described in detail in the description part of the invention.Therefore, it is to be understood that the terms should be defined basedupon their meaning not their simple title and the whole description ofthe present invention.

Among the terms used in the description of the present invention, mainservice data correspond to data that can be received by a fixedreceiving system and may include audio/video (A/V) data. Morespecifically, the main service data may include A/V data of highdefinition (HD) or standard definition (SD) levels and may also includediverse data types required for data broadcasting. Also, the known datacorrespond to data pre-known in accordance with a pre-arranged agreementbetween the receiving system and the transmitting system.

Additionally, among the terms used in the present invention, “MH”corresponds to the initials of “mobile” and “handheld” and representsthe opposite concept of a fixed-type system. Furthermore, the MH servicedata may include at least one of mobile service data and handheldservice data, and will also be referred to as “mobile service data” forsimplicity. Herein, the mobile service data not only correspond to MHservice data but may also include any type of service data with mobileor portable characteristics. Therefore, the mobile service dataaccording to the present invention are not limited only to the MHservice data.

The above-described mobile service data may correspond to data havinginformation, such as program execution files, stock information, and soon, and may also correspond to A/V data. Most particularly, the mobileservice data may correspond to A/V data having lower resolution andlower data rate as compared to the main service data. For example, if anA/V codec that is used for a conventional main service corresponds to aMPEG-2 codec, a MPEG-4 advanced video coding (AVC) or scalable videocoding (SVC) having better image compression efficiency may be used asthe A/V codec for the mobile service. Furthermore, any type of data maybe transmitted as the mobile service data. For example, transportprotocol expert group (TPEG) data for broadcasting real-timetransportation information may be transmitted as the main service data.

Also, a data service using the mobile service data may include weatherforecast services, traffic information services, stock informationservices, viewer participation quiz programs, real-time polls andsurveys, interactive education broadcast programs, gaming services,services providing information on synopsis, character, background music,and filming sites of soap operas or series, services providinginformation on past match scores and player profiles and achievements,and services providing information on product information and programsclassified by service, medium, time, and theme enabling purchase ordersto be processed. Herein, the present invention is not limited only tothe services mentioned above.

In the present invention, the transmitting system provides backwardcompatibility in the main service data so as to be received by theconventional receiving system. Herein, the main service data and themobile service data are multiplexed to the same physical channel andthen transmitted.

Furthermore, the transmitting system according to the present inventionperforms additional encoding on the mobile service data and inserts thedata already known by the receiving system and transmitting system(e.g., known data), thereby transmitting the processed data.

Therefore, when using the transmitting system according to the presentinvention, the receiving system may receive the mobile service dataduring a mobile state and may also receive the mobile service data withstability despite various distortion and noise occurring within thechannel.

Receiving System

FIG. 1 illustrates a block diagram showing a general structure of areceiving system according to an embodiment of the present invention.The receiving system according to the present invention includes abaseband processor 100, a management processor 200, and a presentationprocessor 300.

The baseband processor 100 includes an operation controller 110, a tuner120, a demodulator 130, an equalizer 140, a known sequence detector (orknown data detector) 150, a block decoder (or mobile handheld blockdecoder) 160, a primary Reed-Solomon (RS) frame decoder 170, a secondaryRS frame decoder 180, and a signaling decoder 190.

The operation controller 110 controls the operation of each blockincluded in the baseband processor 100.

By tuning the receiving system to a specific physical channel frequency,the tuner 120 enables the receiving system to receive main service data,which correspond to broadcast signals for fixed-type broadcast receivingsystems, and mobile service data, which correspond to broadcast signalsfor mobile broadcast receiving systems. At this point, the tunedfrequency of the specific physical channel is down-converted to anintermediate frequency (IF) signal, thereby being outputted to thedemodulator 130 and the known sequence detector 140. The passbanddigital IF signal being outputted from the tuner 120 may only includemain service data, or only include mobile service data, or include bothmain service data and mobile service data.

The demodulator 130 performs self-gain control, carrier recovery, andtiming recovery processes on the passband digital IF signal inputtedfrom the tuner 120, thereby translating the IF signal to a basebandsignal. Then, the demodulator 130 outputs the baseband signal to theequalizer 140 and the known sequence detector 150. The demodulator 130uses the known data symbol sequence inputted from the known sequencedetector 150 during the timing and/or carrier recovery, therebyenhancing the demodulating performance.

The equalizer 140 compensates channel-associated distortion included inthe signal demodulated by the demodulator 130. Then, the equalizer 140outputs the distortion-compensated signal to the block decoder 160. Byusing a known data symbol sequence inputted from the known sequencedetector 150, the equalizer 140 may enhance the equalizing performance.Furthermore, the equalizer 140 may receive feed-back on the decodingresult from the block decoder 160, thereby enhancing the equalizingperformance.

The known sequence detector 150 detects known data place (or position)inserted by the transmitting system from the input/output data (i.e.,data prior to being demodulated or data being processed with partialdemodulation). Then, the known sequence detector 150 outputs thedetected known data position information and known data sequencegenerated from the detected position information to the demodulator 130and the equalizer 140. Additionally, in order to allow the block decoder160 to identify the mobile service data that have been processed withadditional encoding by the transmitting system and the main service datathat have not been processed with any additional encoding, the knownsequence detector 150 outputs such corresponding information to theblock decoder 160.

If the data channel-equalized by the equalizer 140 and inputted to theblock decoder 160 correspond to data processed with both block-encodingand trellis-encoding by the transmitting system (i.e., data within theRS frame, signaling data), the block decoder 160 may performtrellis-decoding and block-decoding as inverse processes of thetransmitting system. On the other hand, if the data channel-equalized bythe equalizer 140 and inputted to the block decoder 160 correspond todata processed only with trellis-encoding and not block-encoding by thetransmitting system (i.e., main service data), the block decoder 160 mayperform only trellis-decoding.

The signaling decoder 190 decoded signaling data that have beenchannel-equalized and inputted from the equalizer 140. It is assumedthat the signaling data inputted to the signaling decoder 190 correspondto data processed with both block-encoding and trellis-encoding by thetransmitting system. Examples of such signaling data may includetransmission parameter channel (TPC) data and fast information channel(FIC) data. Each type of data will be described in more detail in alater process. The FIC data decoded by the signaling decoder 190 areoutputted to the FIC handler 215. And, the TPC data decoded by thesignaling decoder 190 are outputted to the TPC handler 214.

Meanwhile, according to the present invention, the transmitting systemuses RS frames by encoding units. Herein, the RS frame may be dividedinto a primary RS frame and a secondary RS frame. However, according tothe embodiment of the present invention, the primary RS frame and thesecondary RS frame will be divided based upon the level of importance ofthe corresponding data.

The primary RS frame decoder 170 receives the data outputted from theblock decoder 160. At this point, according to the embodiment of thepresent invention, the primary RS frame decoder 170 receives only themobile service data that have been Reed-Solomon (RS)-encoded and/orcyclic redundancy check (CRC)-encoded from the block decoder 160.Herein, the primary RS frame decoder 170 receives only the mobileservice data and not the main service data. The primary RS frame decoder170 performs inverse processes of an RS frame encoder (not shown)included in the transmitting system, thereby correcting errors existingwithin the primary RS frame. More specifically, the primary RS framedecoder 170 forms a primary RS frame by grouping a plurality of datagroups and, then, correct errors in primary RS frame units. In otherwords, the primary RS frame decoder 170 decodes primary RS frames, whichare being transmitted for actual broadcast services.

Additionally, the secondary RS frame decoder 180 receives the dataoutputted from the block decoder 160. At this point, according to theembodiment of the present invention, the secondary RS frame decoder 180receives only the mobile service data that have been RS-encoded and/orCRC-encoded from the block decoder 160. Herein, the secondary RS framedecoder 180 receives only the mobile service data and not the mainservice data. The secondary RS frame decoder 180 performs inverseprocesses of an RS frame encoder (not shown) included in thetransmitting system, thereby correcting errors existing within thesecondary RS frame. More specifically, the secondary RS frame decoder180 forms a secondary RS frame by grouping a plurality of data groupsand, then, correct errors in secondary RS frame units. In other words,the secondary RS frame decoder 180 decodes secondary RS frames, whichare being transmitted for mobile audio service data, mobile videoservice data, guide data, and so on.

Meanwhile, the management processor 200 according to an embodiment ofthe present invention includes an MH physical adaptation processor 210,an IP network stack 220, a streaming handler 230, a system information(SI) handler 240, a file handler 250, a multi-purpose internet mainextensions (MIME) type handler 260, and an electronic service guide(ESG) handler 270, and an ESG decoder 280, and a storage unit 290.

The MH physical adaptation processor 210 includes a primary RS framehandler 211, a secondary RS frame handler 212, an MH transport packet(TP) handler 213, a TPC handler 214, an FIC handler 215, and a physicaladaptation control signal handler 216.

The TPC handler 214 receives and processes baseband information requiredby modules corresponding to the MH physical adaptation processor 210.The baseband information is inputted in the form of TPC data. Herein,the TPC handler 214 uses this information to process the FIC data, whichhave been sent from the baseband processor 100.

The TPC data are transmitted from the transmitting system to thereceiving system via a predetermined region of a data group. The TPCdata may include at least one of an MH ensemble ID, an MH sub-framenumber, a total number of MH groups (TNoG), an RS frame continuitycounter, a column size of RS frame (N), and an FIC version number.

Herein, the MH ensemble ID indicates an identification number of each MHensemble carried in the corresponding channel.

The MH sub-frame number signifies a number identifying the MH sub-framenumber in an MH frame, wherein each MH group associated with thecorresponding MH ensemble is transmitted.

The TNoG represents the total number of MH groups including all of theMH groups belonging to all MH parades included in an MH sub-frame.

The RS frame continuity counter indicates a number that serves as acontinuity counter of the RS frames carrying the corresponding MHensemble. Herein, the value of the RS frame continuity counter shall beincremented by 1 modulo 16 for each successive RS frame.

N represents the column size of an RS frame belonging to thecorresponding MH ensemble. Herein, the value of N determines the size ofeach MH TP.

Finally, the FIC version number signifies the version number of an FICcarried on the corresponding physical channel.

As described above, diverse TPC data are inputted to the TPC handler 214via the signaling decoder 190 shown in FIG. 1. Then, the received TPCdata are processed by the TPC handler 214. The received TPC data mayalso be used by the FIC handler 215 in order to process the FIC data.

The FIC handler 215 processes the FIC data by associating the FIC datareceived from the baseband processor 100 with the TPC data.

The physical adaptation control signal handler 216 collects FIC datareceived through the FIC handler 215 and SI data received through RSframes. Then, the physical adaptation control signal handler 216 usesthe collected FIC data and SI data to configure and process IP datagramsand access information of mobile broadcast services. Thereafter, thephysical adaptation control signal handler 216 stores the processed IPdatagrams and access information to the storage unit 290.

The primary RS frame handler 211 identifies primary RS frames receivedfrom the primary RS frame decoder 170 of the baseband processor 100 foreach row unit, so as to configure an MH TP. Thereafter, the primary RSframe handler 211 outputs the configured MH TP to the MH TP handler 213.

The secondary RS frame handler 212 identifies secondary RS framesreceived from the secondary RS frame decoder 180 of the basebandprocessor 100 for each row unit, so as to configure an MH TP.Thereafter, the secondary RS frame handler 212 outputs the configured MHTP to the MH TP handler 213.

The MH transport packet (TP) handler 213 extracts a header from each MHTP received from the primary RS frame handler 211 and the secondary RSframe handler 212, thereby determining the data included in thecorresponding MH TP. Then, when the determined data correspond to SIdata (i.e., SI data that are not encapsulated to IP datagrams), thecorresponding data are outputted to the physical adaptation controlsignal handler 216. Alternatively, when the determined data correspondto an IP datagram, the corresponding data are outputted to the IPnetwork stack 220.

The IP network stack 220 processes broadcast data that are beingtransmitted in the form of IP datagrams. More specifically, the IPnetwork stack 220 processes data that are inputted via user datagramprotocol (UDP), real-time transport protocol (RTP), real-time transportcontrol protocol (RTCP), asynchronous layered coding/layered codingtransport (ALC/LCT), file delivery over unidirectional transport(FLUTE), and so on. Herein, when the processed data correspond tostreaming data, the corresponding data are outputted to the streaminghandler 230. And, when the processed data correspond to data in a fileformat, the corresponding data are outputted to the file handler 250.Finally, when the processed data correspond to SI-associated data, thecorresponding data are outputted to the SI handler 240.

The SI handler 240 receives and processes SI data having the form of IPdatagrams, which are inputted to the IP network stack 220.

When the inputted data associated with SI correspond to MIME-type data,the inputted data are outputted to the MIME-type handler 260.

The MIME-type handler 260 receives the MIME-type SI data outputted fromthe SI handler 240 and processes the received MIME-type SI data.

The file handler 250 receives data from the IP network stack 220 in anobject format in accordance with the ALC/LCT and FLUTE structures. Thefile handler 250 groups the received data to create a file format.Herein, when the corresponding file includes ESG, the file is outputtedto the ESG handler 270. On the other hand, when the corresponding fileincludes data for other file-based services, the file is outputted tothe presentation controller 330 of the presentation processor 300.

The ESG handler 270 processes the ESG data received from the filehandler 250 and stores the processed ESG data to the storage unit 290.Alternatively, the ESG handler 270 may output the processed ESG data tothe ESG decoder 280, thereby allowing the ESG data to be used by the ESGdecoder 280.

The storage unit 290 stores the system information (SI) received fromthe physical adaptation control signal handler 210 and the ESG handler270 therein. Thereafter, the storage unit 290 transmits the stored SIdata to each block.

The ESG decoder 280 either recovers the ESG data and SI data stored inthe storage unit 290 or recovers the ESG data transmitted from the ESGhandler 270. Then, the ESG decoder 280 outputs the recovered data to thepresentation controller 330 in a format that can be outputted to theuser.

The streaming handler 230 receives data from the IP network stack 220,wherein the format of the received data are in accordance with RTPand/or RTCP structures. The streaming handler 230 extracts audio/videostreams from the received data, which are then outputted to theaudio/video (A/V) decoder 310 of the presentation processor 300. Theaudio/video decoder 310 then decodes each of the audio stream and videostream received from the streaming handler 230.

The display module 320 of the presentation processor 300 receives audioand video signals respectively decoded by the A/V decoder 310. Then, thedisplay module 320 provides the received audio and video signals to theuser through a speaker and/or a screen.

The presentation controller 330 corresponds to a controller managingmodules that output data received by the receiving system to the user.

The channel service manager 340 manages an interface with the user,which enables the user to use channel-based broadcast services, such aschannel map management, channel service connection, and so on.

The application manager 350 manages an interface with a user using ESGdisplay or other application services that do not correspond tochannel-based services.

Data Format Structure

Meanwhile, the data structure used in the mobile broadcasting technologyaccording to the embodiment of the present invention may include a datagroup structure and an RS frame structure, which will now be describedin detail.

FIG. 2 illustrates an exemplary structure of a data group according tothe present invention.

FIG. 2 shows an example of dividing a data group according to the datastructure of the present invention into 10 MH blocks (i.e., MH block 1(B1) to MH block 10 (B10)). In this example, each MH block has thelength of 16 segments. Referring to FIG. 2, only the RS parity data areallocated to portions of the previous 5 segments of the MH block 1 (B1)and the next 5 segments of the MH block 10 (B10). The RS parity data areexcluded in regions A to D of the data group.

More specifically, when it is assumed that one data group is dividedinto regions A, B, C, and D, each MH block may be included in any one ofregion A to region D depending upon the characteristic of each MH blockwithin the data group. Herein, the data group is divided into aplurality of regions to be used for different purposes. Morespecifically, a region of the main service data having no interferenceor a very low interference level may be considered to have a moreresistant (or stronger) receiving performance as compared to regionshaving higher interference levels. Additionally, when using a systeminserting and transmitting known data in the data group, wherein theknown data are known based upon an agreement between the transmittingsystem and the receiving system, and when consecutively long known dataare to be periodically inserted in the mobile service data, the knowndata having a predetermined length may be periodically inserted in theregion having no interference from the main service data (i.e., a regionwherein the main service data are not mixed). However, due tointerference from the main service data, it is difficult to periodicallyinsert known data and also to insert consecutively long known data to aregion having interference from the main service data.

Referring to FIG. 2, MH block 4 (B4) to MH block 7 (B7) correspond toregions without interference of the main service data. MH block 4 (B4)to MH block 7 (B7) within the data group shown in FIG. 2 correspond to aregion where no interference from the main service data occurs. In thisexample, a long known data sequence is inserted at both the beginningand end of each MH block. In the description of the present invention,the region including MH block 4 (B4) to MH block 7 (B7) will be referredto as “region A (=B4+B5+B6+B7)”. As described above, when the data groupincludes region A having a long known data sequence inserted at both thebeginning and end of each MH block, the receiving system is capable ofperforming equalization by using the channel information that can beobtained from the known data. Therefore, the strongest equalizingperformance may be yielded (or obtained) from one of region A to regionD.

In the example of the data group shown in FIG. 2, MH block (B3) and MHblock 8 (B8) correspond to a region having little interference from themain service data. Herein, a long known data sequence is inserted inonly one side of each MH block B3 and B8. More specifically, due to theinterference from the main service data, a long known data sequence isinserted at the end of MH block 3 (B3), and another long known datasequence is inserted at the beginning of MH block 8 (B8). In the presentinvention, the region including MH block 3 (B3) and MH block 8 (B8) willbe referred to as “region B (=B3+B8)”. As described above, when the datagroup includes region B having a long known data sequence inserted atonly one side (beginning or end) of each MH block, the receiving systemis capable of performing equalization by using the channel informationthat can be obtained from the known data. Therefore, a strongerequalizing performance as compared to region C/D may be yielded (orobtained).

Referring to FIG. 2, MH block 2 (B2) and MH block 9 (B9) correspond to aregion having more interference from the main service data as comparedto region B. A long known data sequence cannot be inserted in any sideof MH block 2 (B2) and MH block 9 (B9). Herein, the region including MHblock 2 (B2) and MH block 9 (B9) will be referred to as “region C(=B2+B9)”.

Finally, in the example shown in FIG. 2, MH block 1 (B1) and MH block 10(B10) correspond to a region having more interference from the mainservice data as compared to region C. Similarly, a long known datasequence cannot be inserted in any side of MH block 1 (B1) and MH block10 (B10). Herein, the region including MH block 1 (B1) and MH block 10(B10) will be referred to as “region D (=B1+B10)”. Since region C/D isspaced further apart from the known data sequence, when the channelenvironment undergoes frequent and abrupt changes, the receivingperformance of region C/D may be deteriorated.

Additionally, the data group includes a signaling information areawherein signaling information is assigned (or allocated).

In the present invention, the signaling information area may start fromthe 1^(st) segment of the 4^(th) MH block (B4) to a portion of the2^(nd) segment. According to an embodiment of the present invention, thesignaling information area for inserting signaling information may startfrom the 1^(st) segment of the 4^(th) MH block (B4) to a portion of the2^(nd) segment.

More specifically, 276(=207+69) bytes of the 4^(th) MH block (B4) ineach data group are assigned as the signaling information area. In otherwords, the signaling information area consists of 207 bytes of the1^(st) segment and the first 69 bytes of the 2^(nd) segment of the4^(th) MH block (B4). The 1^(st) segment of the 4^(th) MH block (B4)corresponds to the 17^(th) or 173^(rd) segment of a VSB field.

Herein, the signaling information may be identified by two differenttypes of signaling channels: a transmission parameter channel (TPC) anda fast information channel (FIC).

Herein, the TPC data may include at least one of an MH ensemble ID, anMH sub-frame number, a total number of MH groups (TNoG), an RS framecontinuity counter, a column size of RS frame (N), and an FIC versionnumber. However, the TPC data (or information) presented herein aremerely exemplary. And, since the adding or deleting of signalinginformation included in the TPC data may be easily adjusted and modifiedby one skilled in the art, the present invention will, therefore, not belimited to the examples set forth herein. Furthermore, the FIC isprovided to enable a fast service acquisition of data receivers, and theFIC includes cross layer information between the physical layer and theupper layer(s).

For example, when the data group includes 6 known data sequences, asshown in FIG. 2, the signaling information area is located between thefirst known data sequence and the second known data sequence. Morespecifically, the first known data sequence is inserted in the last 2segments of the 3^(rd) MH block (B3), and the second known data sequencein inserted in the 2^(nd) and 3^(rd) segments of the 4^(th) MH block(B4). Furthermore, the 3^(rd) to 6^(th) known data sequences arerespectively inserted in the last 2 segments of each of the 4^(th),5^(th), 6^(th), and 7^(th) MH blocks (B4, B5, B6, and B7). The 1^(st)and 3^(rd) to 6^(th) known data sequences are spaced apart by 16segments.

FIG. 3 illustrates an RS frame according to an embodiment of the presentinvention.

The RS frame shown in FIG. 3 corresponds to a collection of one or moredata groups. The RS frame is received for each MH frame in a conditionwhere the receiving system receives the FIC and processes the receivedFIC and where the receiving system is switched to a time-slicing mode sothat the receiving system can receive MH ensembles including ESG entrypoints. Each RS frame includes IP streams of each service or ESG, andSMT section data may exist in all RS frames.

The RS frame according to the embodiment of the present inventionconsists of at least one MH transport packet (TP). Herein, the MH TPincludes an MH header and an MH payload.

The MH payload may include mobile service data as well as signalingdata. More specifically, an MH payload may include only mobile servicedata, or may include only signaling data, or may include both mobileservice data and signaling data.

According to the embodiment of the present invention, the MH header mayidentify (or distinguish) the data types included in the MH payload.More specifically, when the MH TP includes a first MH header, thisindicates that the MH payload includes only the signaling data. Also,when the MH TP includes a second MH header, this indicates that the MHpayload includes both the signaling data and the mobile service data.Finally, when MH TP includes a third MH header, this indicates that theMH payload includes only the mobile service data.

In the example shown in FIG. 3, the RS frame is assigned with IPdatagrams (IP datagram 1 and IP datagram 2) for two service types.

Data Transmission Structure

FIG. 4 illustrates a structure of a MH frame for transmitting andreceiving mobile service data according to the present invention. In theexample shown in FIG. 4, one MH frame consists of 5 sub-frames, whereineach sub-frame includes 16 slots. In this case, the MH frame accordingto the present invention includes 5 sub-frames and 80 slots.

Also, in a packet level, one slot is configured of 156 data packets(i.e., transport stream packets), and in a symbol level, one slot isconfigured of 156 data segments. Herein, the size of one slotcorresponds to one half (½) of a VSB field. More specifically, since one207-byte data packet has the same amount of data as a data segment, adata packet prior to being interleaved may also be used as a datasegment. At this point, two VSB fields are grouped to form a VSB frame.

FIG. 5 illustrates an exemplary structure of a VSB frame, wherein oneVSB frame consists of 2 VSB fields (i.e., an odd field and an evenfield). Herein, each VSB field includes a field synchronization segmentand 312 data segments.

The slot corresponds to a basic time unit for multiplexing the mobileservice data and the main service data. Herein, one slot may eitherinclude the mobile service data or be configured only of the mainservice data.

If the first 118 data packets within the slot correspond to a datagroup, the remaining 38 data packets become the main service datapackets. In another example, when no data group exists in a slot, thecorresponding slot is configured of 156 main service data packets.

Meanwhile, when the slots are assigned to a VSB frame, an off-set existsfor each assigned position.

FIG. 6 illustrates a mapping example of the positions to which the first4 slots of a sub-frame are assigned with respect to a VSB frame in aspatial area. And, FIG. 7 illustrates a mapping example of the positionsto which the first 4 slots of a sub-frame are assigned with respect to aVSB frame in a chronological (or time) area.

Referring to FIG. 6 and FIG. 7, a 38^(th) data packet (TS packet #37) ofa 1^(st) slot (Slot #0) is mapped to the 1^(st) data packet of an oddVSB field. A 38^(th) data packet (TS packet #37) of a 2^(nd) slot (Slot#1) is mapped to the 157^(th) data packet of an odd VSB field. Also, a38^(th) data packet (TS packet #37) of a 3^(rd) slot (Slot #2) is mappedto the 1^(st) data packet of an even VSB field. And, a 38^(th) datapacket (TS packet #37) of a 4^(th) slot (Slot #3) is mapped to the157^(th) data packet of an even VSB field. Similarly, the remaining 12slots within the corresponding sub-frame are mapped in the subsequentVSB frames using the same method.

FIG. 8 illustrates an exemplary assignment order of data groups beingassigned to one of 5 sub-frames, wherein the 5 sub-frames configure anMH frame. For example, the method of assigning data groups may beidentically applied to all MH frames or differently applied to each MHframe. Furthermore, the method of assigning data groups may beidentically applied to all sub-frames or differently applied to eachsub-frame. At this point, when it is assumed that the data groups areassigned using the same method in all sub-frames of the corresponding MHframe, the total number of data groups being assigned to an MH frame isequal to a multiple of ‘5’.

According to the embodiment of the present invention, a plurality ofconsecutive data groups is assigned to be spaced as far apart from oneanother as possible within the sub-frame. Thus, the system can becapable of responding promptly and effectively to any burst error thatmay occur within a sub-frame.

For example, when it is assumed that 3 data groups are assigned to asub-frame, the data groups are assigned to a 1^(st) slot (Slot #0), a5^(th) slot (Slot #4), and a 9^(th) slot (Slot #8) in the sub-frame,respectively. FIG. 8 illustrates an example of assigning 16 data groupsin one sub-frame using the above-described pattern (or rule). In otherwords, each data group is serially assigned to 16 slots corresponding tothe following numbers: 0, 8, 4, 12, 1, 9, 5, 13, 2, 10, 6, 14, 3, 11, 7,and 15. Equation 1 below shows the above-described rule (or pattern) forassigning data groups in a sub-frame.j=(4i+0)mod 16  Equation 1

-   -   0=0 if i<4,    -   0=2 else if i<8,

Herein,

-   -   0=1 else if i<12,    -   0=3 else.

Herein, j indicates the slot number within a sub-frame. The value of jmay range from 0 to 15 (i.e., 0≦j≦15). Also, variable i indicates thedata group number. The value of i may range from 0 to 15 (i.e., 0≦i≦15).

In the present invention, a collection of data groups included in a MHframe will be referred to as a “parade”. Based upon the RS frame mode,the parade transmits data of at least one specific RS frame.

The mobile service data within one RS frame may be assigned either toall of regions A/B/C/D within the corresponding data group, or to atleast one of regions A/B/C/D. In the embodiment of the presentinvention, the mobile service data within one RS frame may be assignedeither to all of regions A/B/C/D, or to at least one of regions A/B andregions C/D. If the mobile service data are assigned to the latter case(i.e., one of regions A/B and regions C/D), the RS frame being assignedto regions A/B and the RS frame being assigned to regions C/D within thecorresponding data group are different from one another. According tothe embodiment of the present invention, the RS frame being assigned toregions A/B within the corresponding data group will be referred to as a“primary RS frame”, and the RS frame being assigned to regions C/Dwithin the corresponding data group will be referred to as a “secondaryRS frame”, for simplicity. Also, the primary RS frame and the secondaryRS frame form (or configure) one parade. More specifically, when themobile service data within one RS frame are assigned either to all ofregions A/B/C/D within the corresponding data group, one paradetransmits one RS frame. Conversely, when the mobile service data withinone RS frame are assigned either to at least one of regions A/B andregions C/D, one parade may transmit up to 2 RS frames.

More specifically, the RS frame mode indicates whether a paradetransmits one RS frame, or whether the parade transmits two RS frames.Such RS frame mode is transmitted as the above-described TPC data.

Table 1 below shows an example of the RS frame mode.

TABLE 1 RS frame mode (2 bits) Description 00 There is only one primaryRS frame for all group regions 01 There are two separate RS frames.Primary RS frame for group regions A and B Secondary RS frame for groupregions C and D 10 Reserved 11 Reserved

Table 1 illustrates an example of allocating 2 bits in order to indicatethe RS frame mode. For example, referring to Table 1, when the RS framemode value is equal to ‘00’, this indicates that one parade transmitsone RS frame. And, when the RS frame mode value is equal to ‘01’, thisindicates that one parade transmits two RS frames, i.e., the primary RSframe and the secondary RS frame. More specifically, when the RS framemode value is equal to ‘01’, data of the primary RS frame for regionsA/B are assigned and transmitted to regions A/B of the correspondingdata group. Similarly, data of the secondary RS frame for regions C/Dare assigned and transmitted to regions C/D of the corresponding datagroup.

As described in the assignment of data groups, the parades are alsoassigned to be spaced as far apart from one another as possible withinthe sub-frame. Thus, the system can be capable of responding promptlyand effectively to any burst error that may occur within a sub-frame.

Furthermore, the method of assigning parades may be identically appliedto all MH frames or differently applied to each MH frame. According tothe embodiment of the present invention, the parades may be assigneddifferently for each MH frame and identically for all sub-frames withinan MH frame. More specifically, the MH frame structure may vary by MHframe units. Thus, an ensemble rate may be adjusted on a more frequentand flexible basis.

FIG. 9 illustrates an example of multiple data groups of a single paradebeing assigned (or allocated) to an MH frame. More specifically, FIG. 9illustrates an example of a plurality of data groups included in asingle parade, wherein the number of data groups included in a sub-frameis equal to ‘3’, being allocated to an MH frame.

Referring to FIG. 9, 3 data groups are sequentially assigned to asub-frame at a cycle period of 4 slots. Accordingly, when this processis equally performed in the 5 sub-frames included in the correspondingMH frame, 15 data groups are assigned to a single MH frame. Herein, the15 data groups correspond to data groups included in a parade.Therefore, since one sub-frame is configured of 4 VSB frame, and since 3data groups are included in a sub-frame, the data group of thecorresponding parade is not assigned to one of the 4 VSB frames within asub-frame.

For example, when it is assumed that one parade transmits one RS frame,and that a RS frame encoder (not shown) included in the transmittingsystem performs RS-encoding on the corresponding RS frame, therebyadding 24 bytes of parity data to the corresponding RS frame andtransmitting the processed RS frame, the parity data occupyapproximately 11.37% (=24/(187+24)×100) of the total code word length.Meanwhile, when one sub-frame includes 3 data groups, and when the datagroups included in the parade are assigned, as shown in FIG. 9, a totalof 15 data groups form an RS frame. Accordingly, even when an erroroccurs in an entire data group due to a burst noise within a channel,the percentile is merely 6.67% (=1/15×100). Therefore, the receivingsystem may correct all errors by performing an erasure RS decodingprocess. More specifically, when the erasure RS decoding is performed, anumber of channel errors corresponding to the number of RS parity bytesmay be corrected. By doing so, the receiving system may correct theerror of at least one data group within one parade. Thus, the minimumburst noise length correctable by a RS frame is over 1 VSB frame.

Meanwhile, when data groups of a parade are assigned as shown in FIG. 9,either main service data may be assigned between each data group, ordata groups corresponding to different parades may be assigned betweeneach data group. More specifically, data groups corresponding tomultiple parades may be assigned to one MH frame.

Basically, the method of assigning data groups corresponding to multipleparades is very similar to the method of assigning data groupscorresponding to a single parade. In other words, data groups includedin other parades that are to be assigned to an MH frame are alsorespectively assigned according to a cycle period of 4 slots.

At this point, data groups of a different parade may be sequentiallyassigned to the respective slots in a circular method. Herein, the datagroups are assigned to slots starting from the ones to which data groupsof the previous parade have not yet been assigned.

For example, when it is assumed that data groups corresponding to aparade are assigned as shown in FIG. 9, data groups corresponding to thenext parade may be assigned to a sub-frame starting either from the12^(th) slot of a sub-frame. However, this is merely exemplary. Inanother example, the data groups of the next parade may also besequentially assigned to a different slot within a sub-frame at a cycleperiod of 4 slots starting from the 3^(rd) slot.

FIG. 10 illustrates an example of transmitting 3 parades (Parade #0,Parade #1, and Parade #2) to an MH frame. More specifically, FIG. 10illustrates an example of transmitting parades included in one of 5sub-frames, wherein the 5 sub-frames configure one MH frame.

When the 1^(st) parade (Parade #0) includes 3 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘0’ to ‘2’ for i in Equation 1. Morespecifically, the data groups of the 1^(st) parade (Parade #0) aresequentially assigned to the 1^(st), 5^(th) and 9^(th) slots (Slot #0,Slot #4, and Slot #8) within the sub-frame.

Also, when the 2^(nd) parade includes 2 data groups for each sub-frame,the positions of each data groups within the sub-frames may be obtainedby substituting values ‘3’ and ‘4’ for in Equation 1. More specifically,the data groups of the 2nd parade (Parade #1) are sequentially assignedto the 2^(nd) and 12^(th) slots (Slot #1 and Slot #11) within thesub-frame.

Finally, when the 3^(rd) parade includes 2 data groups for eachsub-frame, the positions of each data groups within the sub-frames maybe obtained by substituting values ‘5’ and ‘6’ for i in Equation 1. Morespecifically, the data groups of the 3^(rd) parade (Parade #2) aresequentially assigned to the 7^(th) and 11^(th) slots (Slot #6 and Slot#10) within the sub-frame.

As described above, data groups of multiple parades may be assigned to asingle MH frame, and, in each sub-frame, the data groups are seriallyallocated to a group space having 4 slots from left to right.

Therefore, a number of groups of one parade per sub-frame (NoG) maycorrespond to any one integer from ‘1’ to ‘8’. Herein, since one MHframe includes 5 sub-frames, the total number of data groups within aparade that can be allocated to an MH frame may correspond to any onemultiple of ‘5’ ranging from ‘5’ to ‘40’.

FIG. 11 illustrates an example of expanding the assignment process of 3parades, shown in FIG. 10, to 5 sub-frames within an MH frame.

FIG. 12 illustrates a data transmission structure according to anembodiment of the present invention, wherein signaling data are includedin a data group so as to be transmitted.

As described above, an MH frame is divided into 5 sub-frames. Datagroups corresponding to a plurality of parades co-exist in eachsub-frame. Herein, the data groups corresponding to each parade aregrouped by MH frame units, thereby configuring a single parade.

The data structure shown in FIG. 12 includes 3 parades, one ESGdedicated channel (EDC) parade (i.e., parade with NoG=1), and 2 serviceparades (i.e., parade with NoG=4 and parade with NoG=3). Also, apredetermined portion of each data group (i.e., 37 bytes/data group) isused for delivering (or sending) FIC information associated with mobileservice data, wherein the FIC information is separately encoded from theRS-encoding process. The FIC region assigned to each data group consistsof one FIC segments. Herein, each segment is interleaved by MH sub-frameunits, thereby configuring an FIC body, which corresponds to a completedFIC transmission structure. However, whenever required, each segment maybe interleaved by MH frame units and not by MH sub-frame units, therebybeing completed in MH frame units.

Meanwhile, the concept of an MH ensemble is applied in the embodiment ofthe present invention, thereby defining a collection (or group) ofservices. Each MH ensemble carries the same QoS and is coded with thesame FEC code. Also, each MH ensemble has the same unique identifier(i.e., ensemble ID) and corresponds to consecutive RS frames.

As shown in FIG. 12, the FIC segment corresponding to each data groupdescribed service information of an MH ensemble to which thecorresponding data group belongs. When FIC segments within a sub-frameare grouped and deinterleaved, all service information of a physicalchannel through which the corresponding FICs are transmitted may beobtained.

Therefore, the receiving system may be able to acquire the channelinformation of the corresponding physical channel, after being processedwith physical channel tuning, during a sub-frame period.

Furthermore, FIG. 12 illustrates a structure further including aseparate EDC parade apart from the service parade and wherein electronicservice guide (ESG) data are transmitted in the 1^(st) slot of eachsub-frame.

Hierarchical Signaling Structure

FIG. 13 illustrates a hierarchical signaling structure according to anembodiment of the present invention. As shown in FIG. 13, the mobilebroadcasting technology according to the embodiment of the presentinvention adopts a signaling method using FIC and SMT. In thedescription of the present invention, the signaling structure will bereferred to as a hierarchical signaling structure.

Hereinafter, a detailed description on how the receiving system accessesa virtual channel via FIC and SMT will now be given with reference toFIG. 13.

The FIC body defined in an MH transport (Ml) identifies the physicallocation of each the data stream for each virtual channel and providesvery high level descriptions of each virtual channel.

Being MH ensemble level signaling information, the service map table(SMT) provides MH ensemble level signaling information. The SMT providesthe IP access information of each virtual channel belonging to therespective MH ensemble within which the SMT is carried. The SMT alsoprovides all IP stream component level information required for thevirtual channel service acquisition.

Referring to FIG. 13, each MH ensemble (i.e., Ensemble 0, Ensemble 1, .. . , Ensemble K) includes a stream information on each associated (orcorresponding) virtual channel (e.g., virtual channel 0 IP stream,virtual channel 1 IP stream, and virtual channel 2 IP stream). Forexample, Ensemble 0 includes virtual channel 0 IP stream and virtualchannel 1 IP stream. And, each MH ensemble includes diverse informationon the associated virtual channel (i.e., Virtual Channel 0 Table Entry,Virtual Channel 0 Access Info, Virtual Channel 1 Table Entry, VirtualChannel 1 Access Info, Virtual Channel 2 Table Entry, Virtual Channel 2Access Info, Virtual Channel N Table Entry, Virtual Channel N AccessInfo, and so on).

The FIC body payload includes information on MH ensembles (e.g.,ensemble_id field, and referred to as “ensemble location” in FIG. 13)and information on a virtual channel associated with the correspondingMH ensemble (e.g., when such information corresponds to amajor_channel_num field and a minor_channel_num field, the informationis expressed as Virtual Channel 0, Virtual Channel 1, . . . , VirtualChannel N in FIG. 13).

The application of the signaling structure in the receiving system willnow be described in detail.

When a user selects a channel he or she wishes to view (hereinafter, theuser-selected channel will be referred to as “channel θ” forsimplicity), the receiving system first parses the received FIC. Then,the receiving system acquires information on an MH ensemble (i.e.,ensemble location), which is associated with the virtual channelcorresponding to channel θ (hereinafter, the corresponding MH ensemblewill be referred to as “MH ensemble θ” for simplicity). By acquiringslots only corresponding to the MH ensemble θ using the time-slicingmethod, the receiving system configures ensemble θ. The ensemble θconfigured as described above, includes an SMT on the associated virtualchannels (including channel θ) and IP streams on the correspondingvirtual channels. Therefore, the receiving system uses the SMT includedin the MH ensemble θ in order to acquire various information on channelθ (e.g., Virtual Channel θ Table Entry) and stream access information onchannel θ (e.g., Virtual Channel θ Access Info). The receiving systemuses the stream access information on channel θ to receive only theassociated IP streams, thereby providing channel θ services to the user.

Fast Information Channel (FIC)

The receiving system according to the present invention adopts the fastinformation channel (FIC) for a faster access to a service that iscurrently being broadcasted.

More specifically, the FIC handler 215 of FIG. 1 parses the FIC body,which corresponds to an FIC transmission structure, and outputs theparsed result to the physical adaptation control signal handler 216.

FIG. 14 illustrates an exemplary FIC body format according to anembodiment of the present invention. According to the embodiment of thepresent invention, the FIC format consists of an FIC body header and anFIC body payload.

Meanwhile, according to the embodiment of the present invention, dataare transmitted through the FIC body header and the FIC body payload inFIC segment units. Each FIC segment has the size of 37 bytes, and eachFIC segment consists of a 2-byte FIC segment header and a 35-byte FICsegment payload. More specifically, an FIC body configured of an FICbody header and an FIC body payload, is segmented in units of 35 databytes, which are then carried in at least one FIC segment within the FICsegment payload, so as to be transmitted.

In the description of the present invention, an example of inserting oneFIC segment in one data group, which is then transmitted, will be given.In this case, the receiving system receives a slot corresponding to eachdata group by using a time-slicing method.

The signaling decoder 190 included in the receiving system shown in FIG.1 collects each FIC segment inserted in each data group. Then, thesignaling decoder 190 uses the collected FIC segments to created asingle FIC body. Thereafter, the signaling decoder 190 performs adecoding process on the FIC body payload of the created FIC body, sothat the decoded FIC body payload corresponds to an encoded result of asignaling encoder (not shown) included in the transmitting system.Subsequently, the decoded FIC body payload is outputted to the FIChandler 215. The FIC handler 215 parses the FIC data included in the FICbody payload, and then outputs the parsed FIC data to the physicaladaptation control signal handler 216. The physical adaptation controlsignal handler 216 uses the inputted FIC data to perform processesassociated with MH ensembles, virtual channels, SMTs, and so on.

According to an embodiment of the present invention, when an FIC body issegmented, and when the size of the last segmented portion is smallerthan 35 data bytes, it is assumed that the lacking number of data bytesin the FIC segment payload is completed with by adding the same numberof stuffing bytes therein, so that the size of the last FIC segment canbe equal to 35 data bytes.

However, it is apparent that the above-described data byte values (i.e.,37 bytes for the FIC segment, 2 bytes for the FIC segment header, and 35bytes for the FIC segment payload) are merely exemplary, and will,therefore, not limit the scope of the present invention.

FIG. 15 illustrates an exemplary bit stream syntax structure withrespect to an FIC segment according to an embodiment of the presentinvention.

Herein, the FIC segment signifies a unit used for transmitting the FICdata. The FIC segment consists of an FIC segment header and an FICsegment payload. Referring to FIG. 15, the FIC segment payloadcorresponds to the portion starting from the ‘for’ loop statement.Meanwhile, the FIC segment header may include a FIC_type field, anerror_indicator field, an FIC_seg_number field, and anFIC_last_seg_number field. A detailed description of each field will nowbe given.

The FIC_type field is a 2-bit field indicating the type of thecorresponding FIC.

The error_indicator field is a 1-bit field, which indicates whether ornot an error has occurred within the FIC segment during datatransmission. If an error has occurred, the value of the error_indicatorfield is set to ‘1’. More specifically, when an error that has failed tobe recovered still remains during the configuration process of the FICsegment, the error_indicator field value is set to ‘1’. Theerror_indicator field enables the receiving system to recognize thepresence of an error within the FIC data.

The FIC_seg_number field is a 4-bit field. Herein, when a single FICbody is divided into a plurality of FIC segments and transmitted, theFIC_seg_number field indicates the number of the corresponding FICsegment.

Finally, the FIC_last_seg_number field is also a 4-bit field. TheFIC_last_seg_number field indicates the number of the last FIC segmentwithin the corresponding FIC body.

FIG. 16 illustrates an exemplary bit stream syntax structure withrespect to a payload of an FIC segment according to the presentinvention, when an FIC type field value is equal to ‘0’.

According to the embodiment of the present invention, the payload of theFIC segment is divided into 3 different regions.

A first region of the FIC segment payload exists only when theFIC_seg_number field value is equal to ‘0’. Herein, the first region mayinclude a current_next_indicator field, an ESG_version field, and atransport_stream_id field. However, depending upon the embodiment of thepresent invention, it may be assumed that each of the 3 fields existsregardless of the FIC_seg_number field.

The current_next_indicator field is a 1-bit field. Thecurrent_next_indicator field acts as an indicator identifying whetherthe corresponding FIC data carry MH ensemble configuration informationof an MH frame including the current FIC segment, or whether thecorresponding FIC data carry MH ensemble configuration information of anext MH frame.

The ESG_version field is a 5-bit field indicating ESG versioninformation. Herein, by providing version information on the serviceguide providing channel of the corresponding ESG, the ESG_version fieldenables the receiving system to notify whether or not the correspondingESG has been updated.

Finally, the transport_stream_id field is a 16-bit field acting as aunique identifier of a broadcast stream through which the correspondingFIC segment is being transmitted.

A second region of the FIC segment payload corresponds to an ensembleloop region, which includes an ensemble_id field, an SI_version field,and a num_channel field.

More specifically, the ensemble_id field is an 8-bit field indicatingidentifiers of an MH ensemble through which MH services are transmitted.The MH services will be described in more detail in a later process.Herein, the ensemble_id field binds the MH services and the MH ensemble.

The SI_version field is a 4-bit field indicating version information ofSI data included in the corresponding ensemble, which is beingtransmitted within the RS frame.

Finally, the num_channel field is an 8-bit field indicating the numberof virtual channel being transmitted via the corresponding ensemble.

A third region of the FIC segment payload a channel loop region, whichincludes a channel_type field, a channel_activity field, a CA indicatorfield, a stand_alone_service_indicator field, a major_channel_num field,and a minor_channel_num field.

The channel_type field is a 5-bit field indicating a service type of thecorresponding virtual channel. For example, the channel_type field mayindicates an audio/video channel, an audio/video and data channel, anaudio-only channel, a data-only channel, a file download channel, an ESGdelivery channel, a notification channel, and so on.

The channel_activity field is a 2-bit field indicating activityinformation of the corresponding virtual channel. More specifically, thechannel_activity field may indicate whether the current virtual channelis providing the current service.

The CA_indicator field is a 1-bit field indicating whether or not aconditional access (CA) is applied to the current virtual channel.

The stand_alone_service_indicator field is also a 1-bit field, whichindicates whether the service of the corresponding virtual channelcorresponds to a stand alone service.

The major_channel_num field is an 8-bit field indicating a major channelnumber of the corresponding virtual channel.

Finally, the minor_channel_num field is also an 8-bit field indicating aminor channel number of the corresponding virtual channel.

Service Table Map

FIG. 17 illustrates an exemplary bit stream syntax structure of aservice map table (hereinafter referred to as “SMT”) according to thepresent invention.

According to the embodiment of the present invention, the SMT isconfigured in an MPEG-2 private section format. However, this will notlimit the scope and spirit of the present invention. The SMT accordingto the embodiment of the present invention includes descriptioninformation for each virtual channel within a single MH ensemble. And,additional information may further be included in each descriptor area.

Herein, the SMT according to the embodiment of the present inventionincludes at least one field and is transmitted from the transmittingsystem to the receiving system.

As described in FIG. 3, the SMT section may be transmitted by beingincluded in the MH TP within the RS frame. In this case, each of the RSframe decoders 170 and 180, shown in FIG. 1, decodes the inputted RSframe, respectively. Then, each of the decoded RS frames is outputted tothe respective RS frame handler 211 and 212. Thereafter, each RS framehandler 211 and 212 identifies the inputted RS frame by row units, so asto create an MH TP, thereby outputting the created MH TP to the MH TPhandler 213.

When it is determined that the corresponding MH TP includes an SMTsection based upon the header in each of the inputted MH TP, the MH TPhandler 213 parses the corresponding SMT section, so as to output the SIdata within the parsed SMT section to the physical adaptation controlsignal handler 216. However, this is limited to when the SMT is notencapsulated to IP datagrams.

Meanwhile, when the SMT is encapsulated to IP datagrams, and when it isdetermined that the corresponding MH TP includes an SMT section basedupon the header in each of the inputted MH TP, the MH TP handler 213outputs the SMT section to the IP network stack 220. Accordingly, the IPnetwork stack 220 performs IP and UDP processes on the inputted SMTsection and, then, outputs the processed SMT section to the SI handler240. The SI handler 240 parses the inputted SMT section and controls thesystem so that the parsed SI data can be stored in the storage unit 290.

The following corresponds to example of the fields that may betransmitted through the SMT.

A table_id field corresponds to an 8-bit unsigned integer number, whichindicates the type of table section. The table_id field allows thecorresponding table to be defined as the service map table (SMT).

A section_syntax_indicator field is a 1-bit field corresponding to anindicator defining the section format of the SLT. For example, thesection format may correspond to MPEG long-form syntax.

A private_indicator field is a 1-bit field indicating whether or not theSMT follows (or is in accordance with) a private section.

A section_length field is a 12-bit field indicating the section lengthof the corresponding SMT.

A transport_stream_id field is a 16-bit field indicating atransport_stream identifier of a physical channel transmitting (ordelivering) the corresponding SMT.

A version_number field is a 5-bit field indicating the version number ofthe corresponding SMT.

A current_next_indicator field is a 1-bit field indicating whether thedata included in subsequent SMT sections are currently applicable.

A section_number field is an 8-bit field indicating the section numberof the corresponding SMT.

A last_section_number field is also an 8-bit field indicating the lastsection number of the corresponding SMT.

An SMT_protocol_version field is an 8-bit field indicating the protocolversion of the corresponding SMT section.

An ensemble_id field is an 8-bit unsigned integer field, whichcorresponds to an ID value associated to the corresponding MH ensemble.Herein, the ensemble_id field may be assigned with a value ranging fromrange ‘0x00’ to ‘0x3F’. It is preferable that the value of theensemble_id field is derived from the parade_id of the TPC data, whichis carried from the baseband processor of MH physical layer subsystem.When the corresponding MH ensemble is transmitted through (or carriedover) the primary RS frame, a value of ‘0’ may be used for the mostsignificant bit (MSB), and the remaining 7 bits are used as theparade_id value of the associated MH parade (i.e., for the leastsignificant 7 bits). Alternatively, when the corresponding MH ensembleis transmitted through (or carried over) the secondary RS frame, a valueof ‘1’ may be used for the most significant bit (MSB).

A num_channels field is an 8-bit field, which specifies the number ofvirtual channels in the corresponding SMT section.

Meanwhile, the SMT according to the embodiment of the present inventionprovides information on a plurality of virtual channels using the ‘for’loop statement.

A major_channel_num field corresponds to an 8-bit field, whichrepresents the major channel number associated with the correspondingvirtual channel. Herein, the major_channel_num field may be assignedwith a value ranging from ‘0x00’ to ‘0xFF’.

A minor_channel_num field corresponds to an 8-bit field, whichrepresents the minor channel number associated with the correspondingvirtual channel. Herein, the minor_channel_num field may be assignedwith a value ranging from ‘0x00’ to ‘0xFF’.

A short_channel_name field indicates the short name of the virtualchannel. The service_id field is a 16-bit unsigned integer number (orvalue), which identifies the virtual channel service.

A service_type field is a 6-bit enumerated type field, which designatesthe type of service carried in the corresponding virtual channel asdefined in Table 2 below.

TABLE 2 0x00 [Reserved] 0x01 MH_digital_television field: the virtualchannel carries television programming (audio, video and optionalassociated data) conforming to ATSC standards. 0x02 MH_audio field: thevirtual channel carries audio programming (audio service and optionalassociated data) conforming to ATSC standards. 0x03 MH_data_only_servicefield: the virtual channel carries a data service conforming to ATSCstandards, but no video or audio component. 0x04 to [Reserved for futureATSC usage] 0xFF

A virtual_channel_activity field is a 2-bit enumerated field identifyingthe activity status of the corresponding virtual channel. When the mostsignificant bit (MSB) of the virtual_channel_activity field is ‘1’, thevirtual channel is active, and when the most significant bit (MSB) ofthe virtual_channel_activity field is ‘0’, the virtual channel isinactive. Also, when the least significant bit (LSB) of thevirtual_channel_activity field is ‘1’, the virtual channel is hidden(when set to 1), and when the least significant bit (LSB) of thevirtual_channel_activity field is ‘0’, the virtual channel is nothidden.

A num_components field is a 5-bit field, which specifies the number ofIP stream components in the corresponding virtual channel.

An IP_version_flag field corresponds to a 1-bit indicator. Morespecifically, when the value of the IP_version_flag field is set to ‘1’,this indicates that a source_IP_address field, avirtual_channel_target_IP_address field, and acomponent_target_IP_address field are IPv6 addresses. Alternatively,when the value of the IP_version_flag field is set to ‘0’, thisindicates that the source_IP_address field, thevirtual_channel_target_IP_address field, and thecomponent_target_IP_address field are IPv4.

A source_IP_address_flag field is a 1-bit Boolean flag, which indicates,when set, that a source_IP_address of the corresponding virtual channelexist for a specific multicast source.

A virtual_channel_target_IP_address_flag field is a 1-bit Boolean flag,which indicates, when set, that the corresponding IP stream component isdelivered through IP datagrams with target IP addresses different fromthe virtual_channel_target_IP_address. Therefore, when the flag is set,the receiving system (or receiver) uses the component_target_IP_addressas the target_IP_address in order to access the corresponding IP streamcomponent. Accordingly, the receiving system (or receiver) may ignorethe virtual_channel_target_IP_address field included in the num_channelsloop.

The source_IP_address field corresponds to a 32-bit or 128-bit field.Herein, the source_IP_address field will be significant (or present),when the value of the source_IP_address_flag field is set to ‘1’.However, when the value of the source_IP_address_flag field is set to‘0’, the source_IP_address field will become insignificant (or absent).More specifically, when the source_IP_address_flag field value is set to‘1’, and when the IP_version_flag field value is set to ‘0’, thesource_IP_address field indicates a 32-bit IPv4 address, which shows thesource of the corresponding virtual channel. Alternatively, when theIP_version_flag field value is set to ‘1’, the source_IP_address fieldindicates a 128-bit IPv6 address, which shows the source of thecorresponding virtual channel.

The virtual_channel_target_IP_address field also corresponds to a 32-bitor 128-bit field. Herein, the virtual_channel_target_IP_address fieldwill be significant (or present), when the value of thevirtual_channel_target_IP_address_flag field is set to ‘1’.

However, when the value of the virtual_channel_target_IP_address_flagfield is set to ‘0’, the virtual_channel_target_IP_address field willbecome insignificant (or absent). More specifically, when thevirtual_channel_target_IP_address_flag field value is set to ‘1’, andwhen the IP_version_flag field value is set to ‘0’, thevirtual_channel_target_IP_address field indicates a 32-bit target IPv4address associated to the corresponding virtual channel. Alternatively,when the virtual_channel_target_IP_address_flag field value is set to‘1’, and when the IP_version_flag field value is set to ‘1’, thevirtual_channel_target_IP_address field indicates a 64-bit target IPv6address associated to the corresponding virtual channel. If thevirtual_channel_target_IP_address field is insignificant (or absent),the component_target_IP_address field within the num_channels loopshould become significant (or present). And, in order to enable thereceiving system to access the IP stream component, thecomponent_target_IP_address field should be used.

The EMT_activity_flag field indicates whether program table informationincluding additional information associated with the correspondingensemble exists. The program table information may describe informationon an additional service that is not described in a service of thecorresponding ensemble in the SMT. Herein, the program table informationwill be referred to as an extended service map table (EMT). And, the EMTwill now be described in more detail. The receiving system (or receiver)uses the EMT_activity_flag field to determine whether an extendedservice map table (EMT), which describes additional service informationassociated with the corresponding SMT, is additionally transmitted inthe broadcast signal. For example, when the EMT_activity_flag fieldvalue is equal to ‘1’, the EMT is transmitted to the correspondingensemble. On the other hand, when the EMT_activity_flag field value isequal to ‘0’, the EMT is not transmitted to the corresponding ensemble.

Meanwhile, the SMT according to the embodiment of the present inventionuses a ‘for’ loop statement in order to provide information on aplurality of components.

Herein, an RTP_payload_type field, which is assigned with 7 bits,identifies the encoding format of the component based upon Table 3 shownbelow. When the IP stream component is not encapsulated to RTP, theRTP_payload_type field shall be ignored (or deprecated).

Table 3 below shows an example of the RTP_payload_type.

TABLE 3 RTP_payload_type Meaning 35 AVC video 36 MH audio 37 to 72[Reserved for future ATSC use]

A component_target_IP_address_flag field is a 1-bit Boolean flag, whichindicates, when set, that the corresponding IP stream component isdelivered through IP datagrams with target IP addresses different fromthe virtual_channel_target_IP_address. Furthermore, when thecomponent_target_IP_address_flag is set, the receiving system (orreceiver) uses the component_target_IP_address field as the target IPaddress for accessing the corresponding IP stream component.Accordingly, the receiving system (or receiver) will ignore thevirtual_channel_target_IP_address field included in the num_channelsloop.

The component_target_IP_address field corresponds to a 32-bit or 128-bitfield. Herein, when the value of the IP_version_flag field is set to‘0’, the component_target_IP_address field indicates a 32-bit targetIPv4 address associated to the corresponding IP stream component. And,when the value of the IP_version_flag field is set to ‘1’, thecomponent_target_IP_address field indicates a 128-bit target IPv6address associated to the corresponding IP stream component.

A port_num_count field is a 6-bit field, which indicates the number ofUDP ports associated with the corresponding IP stream component. Atarget UDP port number value starts from the target_UDP_port_num fieldvalue and increases (or is incremented) by 1. For the RTP stream, thetarget UDP port number should start from the target_UDP_port_num fieldvalue and shall increase (or be incremented) by 2. This is toincorporate RTCP streams associated with the RTP streams.

A target_UDP_port_num field is a 16-bit unsigned integer field, whichrepresents the target UDP port number for the corresponding IP streamcomponent. When used for RTP streams, the value of thetarget_UDP_port_num field shall correspond to an even number. And, thenext higher value shall represent the target UDP port number of theassociated RTCP stream.

A component_level_descriptor( ) represents zero or more descriptorsproviding additional information on the corresponding IP streamcomponent.

A virtual_channel_level_descriptor( ) represents zero or moredescriptors providing additional information for the correspondingvirtual channel.

An ensemble_level_descriptor( ) represents zero or more descriptorsproviding additional information for the MH ensemble, which is describedby the corresponding SMT.

FIG. 18 illustrates an exemplary bit stream syntax structure of an MHaudio descriptor according to the present invention.

When at least one audio service is present as a component of the currentevent, the MH_audio_descriptor( ) shall be used as acomponent_level_descriptor of the SMT. The MH_audio_descriptor( ) may becapable of informing the system of the audio language type and stereomode status. If there is no audio service associated with the currentevent, then it is preferable that the MH_audio_descriptor( ) isconsidered to be insignificant (or absent) for the current event.

Each field shown in the bit stream syntax of FIG. 18 will now bedescribed in detail.

A descriptor_tag field is an 8-bit unsigned integer having a TBD value,which indicates that the corresponding descriptor is theMH_audio_descriptor( ).

A descriptor_length field is also an 8-bit unsigned integer, whichindicates the length (in bytes) of the portion immediately following thedescriptor_length field up to the end of the MH_audio_descriptor( ).

A channel_configuration field corresponds to an 8-bit field indicatingthe number and configuration of audio channels. The values ranging from‘1’ to ‘6’ respectively indicate the number and configuration of audiochannels as given for “Default bit stream index number” in Table 42 ofISO/IEC 13818-7:2006. All other values indicate that the number andconfiguration of audio channels are undefined.

A sample_rate_code field is a 3-bit field, which indicates the samplerate of the encoded audio data. Herein, the indication may correspond toone specific sample rate, or may correspond to a set of values thatinclude the sample rate of the encoded audio data as defined in TableA3.3 of ATSC A/52B.

A bit_rate_code field corresponds to a 6-bit field. Herein, among the 6bits, the lower 5 bits indicate a nominal bit rate. More specifically,when the most significant bit (MSB) is ‘0’, the corresponding bit rateis exact. On the other hand, when the most significant bit (MSB) is ‘0’,the bit rate corresponds to an upper limit as defined in Table A3.4 ofATSC A/53B.

An ISO_(—)639_language_code field is a 24-bit (i.e., 3-byte) fieldindicating the language used for the audio stream component, inconformance with ISO 639.2/B [x]. When a specific language is notpresent in the corresponding audio stream component, the value of eachbyte will be set to ‘0x00’.

FIG. 19 illustrates an exemplary bit stream syntax structure of an MHRTP payload type descriptor according to the present invention.

The MH_RTP_payload_type_descriptor( ) specifies the RTP payload type.Yet, the MH_RTP_payload_type_descriptor( ) exists only when the dynamicvalue of the RTP_payload_type field within the num_components loop ofthe SMT is in the range of ‘96’ to ‘127’. TheMH_RTP_payload_type_descriptor( ) is used as acomponent_level_descriptor of the SMT.

The MH_RTP_payload_type_descriptor translates (or matches) a dynamicRTP_payload_type field value into (or with) a MIME type. Accordingly,the receiving system (or receiver) may collect (or gather) the encodingformat of the IP stream component, which is encapsulated in RTP.

The fields included in the MH_RTP_payload_type_descriptor( ) will now bedescribed in detail.

A descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_RTP_payload_type_descriptor( ).

A descriptor_length field also corresponds to an 8-bit unsigned integer,which indicates the length (in bytes) of the portion immediatelyfollowing the descriptor_length field up to the end of theMH_RTP_payload_type_descriptor( ).

An RTP_payload_type field corresponds to a 7-bit field, which identifiesthe encoding format of the IP stream component. Herein, the dynamicvalue of the RTP_payload_type field is in the range of ‘96’ to ‘127’.

A MIME_type_length field specifies the length (in bytes) of a MIME_typefield.

The MIME_type field indicates the MIME type corresponding to theencoding format of the IP stream component, which is described by theMH_RTP_payload_type_descriptor( ).

FIG. 20 illustrates an exemplary bit stream syntax structure of an MHcurrent event descriptor according to the present invention.

The MH_current_event_descriptor( ) shall be used as thevirtual_channel_level_descriptor( ) within the SMT. Herein, theMH_current_event_descriptor( ) provides basic information on the currentevent (e.g., the start time, duration, and title of the current event,etc.), which is transmitted via the respective virtual channel.

The fields included in the MH_current_event_descriptor( ) will now bedescribed in detail.

A descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_current_event_descriptor( ).

A descriptor_length field also corresponds to an 8-bit unsigned integer,which indicates the length (in bytes) of the portion immediatelyfollowing the descriptor_length field up to the end of theMH_current_event_descriptor( ).

An event_id field corresponds to a 16-bit field representing anidentifier for identifying the corresponding event.

A current_event_start_time field corresponds to a 32-bit unsignedinteger quantity. The current_event_start_time field represents thestart time of the current event and, more specifically, as the number ofGPS seconds since 00:00:00 UTC, Jan. 6, 1980.

A current_event_duration field corresponds to a 24-bit field. Herein,the current_event_duration field indicates the duration of the currentevent in hours, minutes, and seconds (wherein the format is in 6 digits,4-bit BCD=24 bits).

A title_length field specifies the length (in bytes) of a title_textfield. Herein, the value ‘0’ indicates that there are no titles existingfor the corresponding event.

The title_text field indicates the title of the corresponding event inevent title in the format of a multiple string structure as defined inATSC A/65C [x].

FIG. 21 illustrates an exemplary bit stream syntax structure of an MHnext event descriptor according to the present invention.

The optional MH_next_event_descriptor( ) shall be used as thevirtual_channel_level_descriptor( ) within the SMT. Herein, theMH_next_event_descriptor( ) provides basic information on the next event(e.g., the start time, duration, and title of the next event, etc.),which is transmitted via the respective virtual channel.

The fields included in the MH_next_event_descriptor( ) will now bedescribed in detail.

A descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_next_event_descriptor( ).

A descriptor_length field also corresponds to an 8-bit unsigned integer,which indicates the length (in bytes) of the portion immediatelyfollowing the descriptor_length field up to the end of theMH_next_event_descriptor( ).

An event_id field corresponds to a 16-bit field representing anidentifier for identifying the corresponding event.

A next_event_start_time field corresponds to a 32-bit unsigned integerquantity. The next_event_start_time field represents the start time ofthe next event and, more specifically, as the number of GPS secondssince 00:00:00 UTC, Jan. 6, 1980.

A next_event_duration field corresponds to a 24-bit field. Herein, thenext_event_duration field indicates the duration of the next event inhours, minutes, and seconds (wherein the format is in 6 digits, 4-bitBCD=24 bits).

A title_length field specifies the length (in bytes) of a title_textfield. Herein, the value ‘0’ indicates that there are no titles existingfor the corresponding event.

The title_text field indicates the title of the corresponding event inevent title in the format of a multiple string structure as defined inATSC A/65C [x].

FIG. 22 illustrates an exemplary bit stream syntax structure of an MHsystem time descriptor according to the present invention.

The MH_system_time_descriptor( ) shall be used as theensemble_level_descriptor( ) within the SMT. Herein, theMH_system_time_descriptor( ) provides information on current time anddate. The MH_system_time_descriptor( ) also provides information on thetime zone in which the transmitting system (or transmitter) transmittingthe corresponding broadcast stream is located, while taking intoconsideration the mobile/portable characteristics of the MH servicedata.

The fields included in the MH_system_time_descriptor( ) will now bedescribed in detail.

A descriptor_tag field corresponds to an 8-bit unsigned integer havingthe value TBD, which identifies the current descriptor as theMH_system_time_descriptor( ).

A descriptor_length field also corresponds to an 8-bit unsigned integer,which indicates the length (in bytes) of the portion immediatelyfollowing the descriptor_length field up to the end of theMH_system_time_descriptor( ).

A system_time field corresponds to a 32-bit unsigned integer quantity.The system_time field represents the current system time and, morespecifically, as the number of GPS seconds since 00:00:00 UTC, Jan. 6,1980.

A GPS_UTC_offset field corresponds to an 8-bit unsigned integer, whichdefines the current offset in whole seconds between GPS and UTC timestandards. In order to convert GPS time to UTC time, the GPS_UTC_offsetis subtracted from GPS time. Whenever the International Bureau ofWeights and Measures decides that the current offset is too far inerror, an additional leap second may be added (or subtracted).Accordingly, the GPS_UTC_offset field value will reflect the change.

A time_zone_offset_polarity field is a 1-bit field, which indicateswhether the time of the time zone, in which the broadcast station islocated, exceeds (or leads or is faster) or falls behind (or lags or isslower) than the UTC time. When the value of thetime_zone_offset_polarity field is equal to ‘0’, this indicates that thetime on the current time zone exceeds the UTC time. Therefore, atime_zone_offset field value is added to the UTC time value. Conversely,when the value of the time_zone_offset_polarity field is equal to ‘1’,this indicates that the time on the current time zone falls behind theUTC time. Therefore, the time_zone_offset field value is subtracted fromthe UTC time value.

The time_zone_offset field is a 31-bit unsigned integer quantity. Morespecifically, the time_zone_offset field represents, in GPS seconds, thetime offset of the time zone in which the broadcast station is located,when compared to the UTC time.

A daylight_savings field corresponds to a 16-bit field providinginformation on the Summer Time (i.e., the Daylight Savings Time).

A time_zone field corresponds to a (5×8)-bit field indicating the timezone, in which the transmitting system (or transmitter) transmitting thecorresponding broadcast stream is located.

FIG. 23 illustrates segmentation and encapsulation processes of aservice map table (SMT) according to the present invention.

According to the present invention, the SMT is encapsulated to UDP,while including a target IP address and a target UDP port number withinthe IP datagram. More specifically, the SMT is first segmented into apredetermined number of sections, then encapsulated to a UDP header, andfinally encapsulated to an IP header.

In addition, the SMT section provides signaling information on allvirtual channel included in the MH ensemble including the correspondingSMT section. At least one SMT section describing the MH ensemble isincluded in each RS frame included in the corresponding MH ensemble.Finally, each SMT section is identified by an ensemble_id included ineach section.

According to the embodiment of the present invention, by informing thereceiving system of the target IP address and target UDP port number,the corresponding data (i.e., target IP address and target UDP portnumber) may be parsed without having the receiving system to request forother additional information.

For example, when the EMT_activity_flag field value in the SMT is equalto ‘1’ (i.e., when information that EMT is to be transmitted is set up),the EMT linked to the SMT may be transmitted to the ensemble, in whichthe SMT is transmitted. Just as the SMT, the EMT may be transmitted toeach ensemble by sections, which is the transmission unit of the EMT.Herein, the EMT may include a descriptor that describes the additionalservices transmitted by each ensemble. In the example shown in FIG. 24,information are set to indicate that the EMT is being transmitted to theSMT of both Ensemble 1 and Ensemble K. Furthermore, it is also indicatedthat EMT section 1, which is linked to SMT Section 1, and EMT section M,which is linked to SMT Section K, are also transmitted to Ensemble 1 andEnsemble K, respectively. Contents of the EMT will hereinafter bedescribed in detail.

FIG. 24 illustrates a flow chart for accessing a virtual channel usingFIC and SMT according to the present invention.

More specifically, a physical channel is tuned (S501). And, when it isdetermined that an MH signal exists in the tuned physical channel(S502), the corresponding MH signal is demodulated (S503). Additionally,FIC segments are grouped from the demodulated MH signal in sub-frameunits (S504 and S505).

According to the embodiment of the present invention, an FIC segment isinserted in a data group, so as to be transmitted. More specifically,the FIC segment corresponding to each data group described serviceinformation on the MH ensemble to which the corresponding data groupbelongs. When the FIC segments are grouped in sub-frame units and, then,deinterleaved, all service information on the physical channel throughwhich the corresponding FIC segment is transmitted may be acquired.Therefore, after the tuning process, the receiving system may acquirechannel information on the corresponding physical channel during asub-frame period. Once the FIC segments are grouped, in S504 and S505, abroadcast stream through which the corresponding FIC segment is beingtransmitted is identified (S506). For example, the broadcast stream maybe identified by parsing the transport_stream_id field of the FIC body,which is configured by grouping the FIC segments.

Furthermore, an ensemble identifier, a major channel number, a minorchannel number, channel type information, and so on, are extracted fromthe FIC body (S507). And, by using the extracted ensemble information,only the slots corresponding to the designated ensemble are acquired byusing the time-slicing method, so as to configure an ensemble (S508).

Subsequently, the RS frame corresponding to the designated ensemble isdecoded (S509), and an IP socket is opened for SMT reception (S510).

According to the example given in the embodiment of the presentinvention, the SMT is encapsulated to UDP, while including a target IPaddress and a target UDP port number within the IP datagram. Morespecifically, the SMT is first segmented into a predetermined number ofsections, then encapsulated to a UDP header, and finally encapsulated toan IP header. According to the embodiment of the present invention, byinforming the receiving system of the target IP address and target UDPport number, the receiving system parses the SMT sections and thedescriptors of each SMT section without requesting for other additionalinformation (S511).

The SMT section provides signaling information on all virtual channelincluded in the MH ensemble including the corresponding SMT section. Atleast one SMT section describing the MH ensemble is included in each RSframe included in the corresponding MH ensemble. Also, each SMT sectionis identified by an ensemble_id included in each section. The SMT mayinclude information indicating whether or not EMT, which transmitsinformation on additional services, is transmitted to the correspondingensemble.

Furthermore each SMT provides IP access information on each virtualchannel subordinate to the corresponding MH ensemble including each SMT.Finally, the SMT provides IP stream component level information requiredfor the servicing of the corresponding virtual channel.

Therefore, by using the information parsed from the SMT, the IP streamcomponent belonging to the virtual channel requested for reception maybe accessed (S513). Accordingly, the service associated with thecorresponding virtual channel is provided to the user (S514).

If it is determined in Step 512 that the SMT includes informationindicating that an EMT exists in the corresponding ensemble (S515:‘YES’), the EMT may be parsed in the corresponding ensemble so as toacquire the additional information (S516). Thereafter, by using theinformation acquired in Step 516, the additional services, which cannotbe described by the SMT, may be described, and the correspondingadditional services may then be provided.

FIG. 25 illustrates an exemplary bit stream syntax structure of an EMTaccording to another embodiment of the present invention. Theabove-described SMT may describe a stream included in theservice-providing virtual channel and channel information on thecorresponding virtual channel. And, when the EMT_activity_flag field ofthe SMT is set up, an EMT, which is added to the SMT so as to describethe services that are to be provided, is transmitted.

Accordingly, the SMT may enable audio/video/data streams of thebroadcast signal to be swiftly or quickly outputted from the receivingsystem. And, the EMT may either provide more detailed information oneach virtual channel or describe the additional services.

Contents of the EMT will now be described in detail.

A table_id field is an 8-bit table identifier, which may be set up as anidentifier for identifying the EMT. A section_syntax_indicator fieldcorresponds to an indicator defining the section format of the EMT. Forexample, the section format may correspond to MPEG long-form syntax.

A Private_indicator field indicates whether or not the EMT follows (oris in accordance with) a private section. A reserved field correspondsto a non-designated field, and the value of the reserved field may, forexample, be set to ‘1’.

A section_length field indicates the section length of the correspondingEMT. A transport_stream_id field represents a transport_stream indicatorof a physical channel through which the corresponding EMT is beingtransmitted. Herein, also, a reserved field corresponds to anon-designated field, and the value of the reserved field may, forexample, be set to ‘1’.

A version_number field indicates the version number of the correspondingEMT. A current_next_indicator field indicates whether the data includedin subsequent EMT sections are currently applicable. A section_numberfield indicates the section number of the corresponding EMT.

A last_section_number field indicates the last section number of thecorresponding EMT. An EMT_protocol_version field indicates the protocolversion of the corresponding EMT section.

An ensemble_id field indicates an identification number of the ensemblewhich the EMT describes. A num_channels field indicates the number ofchannels included in the corresponding ensemble.

A major_channel_number field indicates the major channel number of thecorresponding virtual channel, and a minor_channel_number fieldindicates the minor channel number of the corresponding virtual channel.

A num_components field indicates the number of components included inthe corresponding virtual channel.

The EMT may include a descriptor with respect to each level. Forexample, the EMT may include a descriptor for a component level (i.e.,component_level_descriptor), a descriptor for an event level (i.e.,event_level_descriptor), a descriptor for a virtual channel level (i.e.,virtual_channel_level_descriptor), and a descriptor for an ensemblelevel (i.e., ensemble_level_descriptor).

More specifically, the component_level_descriptor may includeinformation on the corresponding component.

A num_events field indicates a number of events included in an event.

And, the event_level_descriptor may include information on thecorresponding event. Furthermore, the virtual_channel_level_descriptorand ensemble descriptor for each virtual channel may respectivelyinclude information on the corresponding virtual channel and thecorresponding ensemble (i.e., ensemble_level_descriptor).

For example, the SMT describes basic information on a virtual channel ofan ensemble, whereas the EMT may deliver (or transmit) additionalservice information or detailed information on additional service withrespect to the virtual channel included in the corresponding ensemblevia descriptors for each level. The descriptor for the EMT may includeprogram guide information for the virtual channel, informationassociated with data broadcasting, information associated withinteractive services, permission information associated with whether ornot access to each virtual channel has been permitted, and so on.

Furthermore, a descriptor for an audio component among the virtualchannel components shown in FIG. 18, a descriptor for which the virtualchannel describes a current/next event, as shown in FIG. 19 and FIG. 20,and a descriptor describing a system time, as shown in FIG. 22, may beincluded in the EMT so as to be transmitted and received.

Also, the above-described EMT (or SMT according to the second embodimentof the present invention) may be divided into constant units, such assection units. Herein, each of the section units may describe anensemble.

When an SMT is received, the SI handler 240 of the receiving systemshown in FIG. 1 may parse the SMT. Herein, when the SI handler 240acquires information indicating that an EMT included in the SMT is beingreceived, the SI handler 240 may receive the EMT from the IP networkstack 220. The SI handler 240 may include an EMT parser, which parsesdetailed information on the virtual channel included in the EMT and,then, stores the parsed information in the storage unit 290. The MHmanagement processor 200 reads the information parsed from the EMT fromthe storage unit 290. Then, the MH management processor 200 delivers (orsends) the read information to the MH baseband processor 100 or the MHpresentation processor 300.

For example, when the information parsed from the EMT corresponds toinformation associated with a current or next event, or when theinformation parsed from the EMT corresponds to information associatedwith data broadcasting, the MH presentation processor 300 may controlthe system so that the information associated with an event orinformation associated with data broadcasting, which is delivered to theEMT, can be displayed to the user.

Furthermore, when the additional information parsed from the EMTcorresponds to permission information on the storage or copying ofspecific broadcast data content, the MH management processor 200 maystore or copy the broadcast data content received from a broadcastsignal based upon the corresponding permission information.

For example, when the application manager activates an application foradditional service, such as data broadcasting, and when the additionalservice information transmitted to the EMT is read from the storage unit290, the corresponding additional service information may be used toprovide the additional service to the user.

Therefore, by using the information delivered to the above-described EMT(or SMT according to the second embodiment of the present invention),the receiving system (or receiver) may provide additional serviceinformation, which is associated with the corresponding ensemble,virtual channel, and component of the virtual channel, to the user alongwith the broadcast signal.

As described above, the present invention may provide a servicetransmitted through a virtual channel by using the SMT. The presentinvention may also identify that the EMT is being transmitted from theSMT. Furthermore, the present invention may acquire detailed additionalinformation associated with the component included in the virtualchannel, the event, the virtual channel, and the ensemble from the EMT.

Meanwhile, in the present invention, the main service data may beretransmitted as mobile service data. More specifically, a broadcastsignal of a single channel may be transmitted as the main service dataand also as the mobile service data.

At this point, the main service data and the mobile service data mayeither be multiplexed to a single channel and then transmitted or berespectively transmitted to a different channel. Hereinafter, the mobileservice data will be considered as retransmitted data of the mainservice data.

The main service data have been developed to be used in high-definitiontelevision (HDTV) receivers. Therefore, the main service data may bedisplayed as high-definition image data on a wide screen. However, beingsensitive to movement, the main service data may be distorted whenprovided to a mobile receiving system. Conversely, the mobile servicedata is robust against movement. However, due to the low resolution ofthe mobile service data, the picture quality of the mobile service dataimage is low when displayed on a wide screen.

Therefore, in a receiving system receiving both main service data andmobile service data, the receiving system according to the presentinvention relates to being capable of automatically selecting one of themain service data and the mobile service data, based upon the receivingcondition (or environment), thereby processing the selected dataaccordingly.

In order to do so, the present invention includes information on channelconfiguration of retransmitted main service data in signalinginformation for mobile services (e.g., FIC or SMT (or EMT)) andtransmits the processed data. Thus, the present invention can enable thereceiving system to easily be informed of the inter-related channel.Additionally, since the A/V stream for the main service is re-encoded asthe A/V stream for the mobile service and then transmitted, an intervalmay occur between the two services. For example, it is assumed that,while program A is being transmitted as the current main service data,program A is simultaneously retransmitted as mobile service data for themobile service. In this case, although program A for the main serviceand program A for the mobile service are transmitted at the same time,the data processing procedure performed by the transmitting system foreach program A may be partially different from one another. Accordingly,program A for the main service may be serviced (or provided) slightlyearlier or later than program A for the mobile service.

Therefore, when switching service modes (or channels), the user mayexperience disturbance (or disconnection) while viewing the broadcastprogram. In order to ensure undisturbed viewing of the requestedprogram, even when the service modes (or channels) are being switched,information on the interval occurring between the two service typesshall be included in the information on channel configuration and thentransmitted.

Hereinafter, the information on the channel configuration of theretransmitted main service data will be referred to as “retransmissionchannel information”.

The retransmission channel information may be transmitted in a fieldformat, in a descriptor format, or in a table format.

According to the embodiment of the present invention, when theretransmission channel information is transmitted in the field format orthe descriptor format, the field format or descriptor format of theretransmission channel information is included in at least one of themobile signaling information for the mobile service (e.g., FIC, SMT, andEMT).

FIG. 26 illustrates an exemplary syntax structure of an FIC segmentincluding retransmission channel information according to an embodimentof the present invention.

Herein, a header of the FIC segment may include an FIC_Type field, anError_Indicator field, an FIC_segment_Number field, and anFIC_Last_segment_Number field. Since each of the above-mentioned fieldsis described with reference to FIG. 15, a detailed description of thesane will be omitted for simplicity.

A payload of the FIC segment may include an ensemble loop and a channelloop. The ensemble loop is repeated as many times as the number ofensembles included in the FIC segment. And, the channel loop is repeatedas many times as the number of channels included in the correspondingensemble. The retransmission channel information of the presentinvention may be included in the ensemble loop or may be included in thechannel loop. According to the embodiment of the present invention, theretransmission channel information is included in the channel loop.

More specifically, the ensemble loop may include an Ensemble_id field, aSignaling_version field, a NumChannels field, and a channel looprepeated as many times as the value of the NumChannels field. TheNumChannels field may indicate the number of virtual channels includedin the ensemble corresponding to the Ensemble_id field value.

The channel loop may include a Channel_type field, a CA_Indicator field,a Stand_alone_Service_Indicator field, a Major_channel_num field, aMinor_channel_num field, and a retransmission channel information field.

Herein, the Channel_type field, the CA_Indicator field, theStand_alone_Service_Indicator field, the Major_channel_num field, andthe Minor_channel_num field each indicate information on the virtualchannel corresponding to the requested mobile service.

The retransmission channel information field may include aretransmission_flag field, a retransmission_major_channel_num field, aretransmission_minor_channel_num field, a retransmission_dir field, anda retransmission_interval field.

More specifically, the retransmission_flag field is a 1-bit fieldindicating whether or not the A/V mobile service of the current virtualchannel is also being provided as the main service. For example, whenthe value of the retransmission_flag field is equal to ‘1’, thisindicates that the corresponding A/V mobile service is also beingprovided as the main service. And, when the value of theretransmission_flag field is equal to ‘0’, this indicates that no mainservice matching with the A/V mobile service of the current virtualchannel exists.

The retransmission_major_channel_num field is an 8-bit field. Herein,when the value of the retransmission_flag field is equal to ‘1’, theretransmission_major_channel_num field indicates the major channelnumber of the matching main service.

The retransmission_minor_channel_num field is also an 8-bit field.Herein, when the value of the retransmission_flag field is equal to ‘1’,the retransmission_minor_channel_num field indicates the minor channelnumber of the matching main service.

The retransmission_dir field is a 1-bit field. Herein, when the value ofthe retransmission_flag field is equal to ‘1’, the retransmission_dirfield indicates a synchronous interval between a main service datastream and a mobile service data stream. For example, when theretransmission_dir field value is equal to ‘0’, the main service datastream is faster than the mobile service data stream. And, conversely,when the retransmission_dir field value is equal to ‘1’, the mainservice data stream is slower than the mobile service data stream.

The retransmission_interval field is a 14-bit field indicating an actualinterval between the mobile service and the main service. According tothe embodiment of the present invention, the retransmission_intervalfield is indicated in ms units.

Furthermore, the order, position, and definition of the retransmissionchannel information fields shown in FIG. 26 are merely examplespresented to facilitate and simplify the understanding of the presentinvention. In other words, the order, position, and definition of theretransmission channel information fields and the number of fields thatmay be additionally allocated may be easily altered or modified by thesystem designer. Therefore, the present invention will not be limited tothe examples given in the above-described embodiment of the presentinvention.

FIG. 27 illustrates an exemplary syntax structure of an SMT sectionincluding retransmission channel information in a field format accordingto an embodiment of the present invention.

Among the fields shown in FIG. 27, description of the fields identicalto those shown in FIG. 17 or FIG. 26 will be omitted for simplicity.

According to the embodiment of the present invention, the retransmissionchannel information is included in the virtual channel loop of eitherthe EMT of FIG. 25 or the SMT of FIG. 27.

More specifically, the retransmission_flag field, theretransmission_major_channel_num field, theretransmission_minor_channel_num field, the retransmission_dir field,and the retransmission_interval field may be positioned after thevirtual_channel_target_IP_address field within the virtual channel loop.

According to the embodiment of the present invention, if theretransmission channel information is transmitted in a descriptorformat, the retransmission channel information, the retransmissionchannel information is transmitted as a virtual channel leveldescriptor.

FIG. 28 illustrates an exemplary syntax structure of an SMT sectionincluding retransmission channel information in a descriptor format,i.e., an MH_Retransmission_Descriptor( ), according to an embodiment ofthe present invention.

In the retransmission channel information descriptorMH_Retransmission_Descriptor( ), the descriptor_tag field is an 8-bitfield indicating that the corresponding descriptor is theMH_Retransmission_Descriptor( ).

The descriptor_length field is an 8-bit field indicating the byte-sizelength starting from the descriptor_length field to the end of theMH_Retransmission_Descriptor( ).

Furthermore, the retransmission_flag field, theretransmission_major_channel_num field, theretransmission_minor_channel_num field, the retransmission_dir field,and the retransmission_interval field are sequentially positioned afterthe descriptor_length field. Herein, since the above-mentioned fieldsare identical to those shown in FIG. 26, detailed description of thesame will be omitted for simplicity.

Meanwhile, the retransmission channel information may also betransmitted in a separate table format.

FIG. 29 illustrates an exemplary syntax structure of a retransmissionchannel information table section, i.e., anMH_Retransmission_table_section( ), according to an embodiment of thepresent invention.

Referring to FIG. 29, a table_ID field indicates that the correspondingtable is a retransmission channel information table.

Herein, the section_syntax_indicator field may be set to have the valueof ‘1’, and this may indicate that a general MPEG-2 section syntaxfollows the section_length field.

The section_length field may define the number of remaining data bytes.Herein, the section_length field may be set to be smaller than ‘4093’.

The current_next_indicator field indicates that the transmitted (ordelivered) table is applicable at all times. Herein, thecurrent_next_indicator field may be set to ‘1’.

The section_number field indicates that the transmitted (or delivered)table shall occupy the length of at least one section. Herein, thesection_number field may be set to have the value of ‘0x00’.

The last_section_number field indicates the last section number of acomplete EAT. The ensemble_id field value corresponds to an ID valueassociated with the corresponding ensemble. The value of the ensemble_idfield may range from ‘0x00’ to ‘0x3F’. The num_channels field indicatesthe number of retransmission channels within the retransmission channelinformation table section.

Meanwhile, the retransmission channel information table according to thepresent invention provides information on multiple retransmissionchannel by using a ‘for’ loop statement. The retransmission_flag field,the retransmission_major_channel_num field, theretransmission_minor_channel_num field, the retransmission_dir field,and the retransmission_interval field are sequentially positioned in the‘for’ loop statement. Herein, since the above-mentioned fields areidentical to those shown in FIG. 26, detailed description of the samewill be omitted for simplicity.

FIG. 30 illustrates a flow chart showing a method for synchronizing themain service and the mobile service according to the present invention.More specifically, when the A/V service, which is currently beingprovided as the main service, is retransmitted as the mobile service,the receiving system receives and stores retransmission channelinformation from any one of FIG. 26 to FIG. 29 (S701). At this point,the receiving system may tune either to a channel for receiving mainservices or to a channel for receiving mobile services (S702). Accordingto the embodiment of the present invention, when the power is turned on,or when the user changes (or switches) the channel, the receiving systemtunes to the channel for receiving main services. If the mobile servicedata and the main service data are transmitted through the same channel,the receiving system may choose any one of a broadcast signal for a mainservice and a broadcast signal for a mobile service both receivedthrough the tuned channel.

Thereafter, the receiving system refers to the retransmission channelinformation in accordance with the receiving condition (or environment)so as to automatically switch to a channel (or broadcast signal) for amain service or to a channel (or broadcast signal) for a mobile service.For example, the receiving system compares a signal-to-noise ratio (SNR)of the main service data and a predetermined threshold value (SNRt)(S703). Then, when the SNR value of the main service data are greaterthan the predetermined threshold value, the receiving system selects thebroadcast signal for the main service and temporarily stores theselected broadcast signal (S704). Thereafter, the receiving systemprovides the main service to the user through a display screen and/or aspeaker (S705).

Alternatively, when the SNR value of the main service data are smallerthan the predetermined threshold value, the receiving system selects thebroadcast signal for the mobile service and temporarily stores theselected broadcast signal (S706). Thereafter, the receiving systemprovides the mobile service to the user through a display screen and/ora speaker (S707). Herein, when the SNR value of the main service dataare greater than the predetermined threshold value, this indicates thatthe receiving system is not moving (i.e., in a stable state). In thiscase, the receiving system switches to the main service mode, whichprovides high picture quality. On the other hand, when the SNR value ofthe main service data are smaller than the predetermined thresholdvalue, this indicates that the receiving system is moving (i.e., in amobile state). Therefore, in this case, the receiving system switches tothe mobile service mode, which is robust against movement.

Herein, since an interval occurs between the main service and the mobileservice, the receiving system according to the present invention refersto interval identification information and interval information withinthe retransmission channel information, so as to perform synchronizationbetween the main service and the mobile service. The predeterminedthreshold value (SNRt) may be arbitrarily defined and used by the user.However, the adequate threshold value would be approximately 10 dB.Instead of using the SNR value of the main service data, the receivingsystem may compare the SNR value of the mobile service data with thepredetermined threshold value in order to perform synchronizationbetween the main service and the mobile service.

FIG. 31 illustrates a block view showing the structure of a receivingsystem according to another embodiment of the present invention. Thereceiving system shown in FIG. 31 includes a host 800, an MH basebandprocessor 811, an RS frame handler 812, an MH A/V decoder 813, an MH A/Vbuffer 814, an output controller 815, a display module 816, an FIChandler 817, an SMT handler 818, a channel/service map database (DB)819, a stream demultiplexer (DEMUX) 822, a main A/V decoder 823, and amain A/V buffer 824. The host 800 may be a CPU, or an operationcontroller 110 shown in FIG. 1, or a physical adaptation control signalhandler 216. The baseband processor 100 shown in FIG. 1 may be directlyapplied as the MH baseband processor 811 without modification. Morespecifically, the RS frame demodulated and error-corrected by the MHbaseband processor 811 is outputted to the RS frame handler 812, and theFIC-chunk is outputted to the FIC handler 817.

The FIC handler 817 parses the FIC-chunk received from the MH basebandprocessor 811. Then, the FIC handler 817 stores the FIC data, whichcorrespond to the parsed result, in the channel/service map DB 819through the host 800. The channel/service map DB 819 stores informationon all service maps that can be accessed by the receiving system.Thereafter, the channel/service map DB 819 provides the correspondinginformation to the host 800 when requested. Herein, the term “access”refers to whether or not the receiving system can recognize the presenceof a service, regardless of whether the receiving system can consume theservice or not. However, when a service provider provides a servicedesignated only to a specific type of receiver (or receiving system),receiving systems other than the designated receiver type may not beable to access the service that is being provided. Herein, thechannel/service map DB 819 may correspond to the storage unit 290 ofFIG. 1. In case the retransmission channel information according to thepresent invention is included in the FIC, as shown in FIG. 26, and thentransmitted, the FIC handler 817 parses the retransmission channelinformation from the FIC, thereby storing the parsed result in thechannel/service map DB 819.

The RS frame handler 812 processes IP-based A/V mobile service data fromthe RS frame transmitted from the MH baseband processor 811 at aconstant time interval (e.g., MH frame) determined by the host 800.Thereafter, the RS frame handler 812 outputs the processed IP-based A/Vmobile service data to the MH A/V decoder 813. The MH A/V decoder 813decodes each of the A/V mobile service data, which are then outputted tothe MH buffer 814 so as to be temporarily stored. Additionally, when anSMT section is included in the RS frame, the RS frame handler 812outputs the SMT section to the SMT handler 818. The SMT handler 818collects (or gathers) at least one SMT section so as to complete an SMT.Thereafter, the SMT handler 818 parses the completed SMT and stores theparsed result in the channel/service map DB 819 through the host 800.When the SMT is parsed, MH ensemble level signaling information, IPaccess information on each virtual channel belonging to thecorresponding MH ensemble including each SMT, and IP stream componentlevel information required for servicing (or providing) thecorresponding virtual channel may be acquired.

If the retransmission channel information according to the presentinvention is included in the SMT in a field format, as shown in FIG. 27,or in a descriptor format, as shown in FIG. 28, and then transmitted,the SMT handler 818 parses the retransmission channel information fromthe SMT, thereby storing the parsed result in the channel/service map DB819. On the other hand, if the retransmission channel informationaccording to the present invention is included in the SMT in a tableformat, as shown in FIG. 29, the SMT handler 818 parses theretransmission channel information and stores the parsed result in thechannel/service map DB 819. In order to perform this process, thereceiving system of FIG. 31 may further include a program table handler.

Meanwhile, the main service data demodulated and error-corrected fromthe main baseband processor 821 are inputted to the stream demultiplexer822, thereby being identified (or distinguished) as the main audioservice data and the main video service data. The main audio servicedata and the main video service data identified by the streammultiplexer 822 are respectively decoded by the main A/V decoder 823 andthen temporarily stored in the main A/V buffer 824. Based upon thecontrol of the host 800, the output controller 815 either selects theoutput of the MH A/V buffer 814 or the output of the main A/V buffer 824and outputs the selected data to the display module 816.

The host 800 controls the output controller 815 so as to select one ofthe output of the MH A/V buffer 814 and the output of the main A/Vbuffer 824, based upon the receiving condition (or environment) (e.g.,the SNR value of the main service data). Herein, according to theembodiment of the present invention, the SNR value of the main servicedata is calculated from the output data of the main baseband processor821.

For example, if the SNR value of the main service data is greater than apredetermined threshold value (SNRt), a control signal for selecting theoutput of the main A/V buffer 824 is outputted to the output controller815. Conversely, if the SNR value of the main service data is smallerthan a predetermined threshold value (SNRt), a control signal forselecting the output of the MH A/V buffer 814 is outputted to the outputcontroller 815.

The display module 816 provides the A/V service outputted from theoutput controller 815 to the user through a display screen and/or aspeaker.

At this point, since an interval occurs between the main service and themobile service, the host 800 refers to the interval identificationinformation and the interval information within the retransmissionchannel information. Accordingly, the host 800 controls the output of MHA/V buffer 814 and the main A/V buffer 824, so as to performsynchronization between the main service and the mobile service.

As described above, the digital broadcasting system and the dataprocessing method of the same have the following advantages. In areceiving system that can simultaneously provide mobile service and mainservice, by automatically switching to high-definition main service ormobile service, which is robust against movement, based upon thereceiving environment (or condition), the receiving system may providethe user with an optimum broadcast service. Furthermore, bysynchronizing the A/V service between the main service and the mobileservice using retransmission channel information includingretransmission status information, channel information, and intervalinformation, an uninterrupted (or continuous) A/V service may beprovided even after switching services. Finally, the present inventionmay also be applied when the main service data are divided into aplurality of SDTV main service data units and then transmitted.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of processing broadcast data in abroadcast transmitter, the method comprising: performing, by a ReedSolomon (RS) encoder, RS encoding and Cyclic Redundancy Check (CRC)encoding on mobile service data to build RS frames belonging to anensemble, wherein each of the RS frames is mapped into data groups thatcomprise known data sequences and a portion of fast information channel(FIC) data including information for rapid mobile service acquisition,wherein the information for rapid mobile service acquisition includestransport stream identification information for identifying a mobilebroadcast carrying a mobile service that includes the mobile servicedata and current and next (C/N) indication information for indicatingwhether the FIC data are applicable to a current transmission frame or anext transmission frame; multiplexing data in the data groups and mainservice data; and transmitting a transmission frame including themultiplexed data in the data groups and the main service data, whereinthe transmission frame comprises sub-frames that comprise slots that aretime periods for multiplexing the mobile service data and the mainservice data, wherein each of the data groups is transmitted during eachof the slots, wherein transmission parameters are transmitted in eachslot during which each data group is transmitted, and wherein thetransmission parameters comprise information for indicating a sub-framenumber that contains the slot and information for indicating a totalnumber of data groups to be transmitted during one sub-frame of thetransmission frame.
 2. The method of claim 1, wherein the transmissionparameters further comprise an ensemble identifier for identifying theensemble.
 3. The method of claim 1, wherein the transmission parametersfurther comprise an RS frame continuity counter for serving as acontinuity indicator of the RS frames carried in the ensemble.
 4. Themethod of claim 1, wherein: the FIC data are divided into a plurality ofFIC segment payloads; and each of the data groups includes an FICsegment comprising an FIC segment header including FIC type informationand one of the plurality of FIC segment payloads.
 5. The method of claim4, wherein the FIC segment header further includes an error indicatorfield indicating whether an error is detected in the FIC segment.
 6. Themethod of claim 1, wherein: at least two of the known data sequences arespaced 16 segments apart; and at least two of the known data sequenceshave different lengths.
 7. A broadcast transmitter comprising: a ReedSolomon (RS) encoder for performing RS encoding and Cyclic RedundancyCheck (CRC) encoding on mobile service data to build RS frames belongingto an ensemble, wherein each of the RS frames is mapped into data groupsthat comprise known data sequences and a portion of fast informationchannel (FIC) data including information for rapid mobile serviceacquisition, wherein the information for rapid mobile serviceacquisition includes transport stream identification information foridentifying a mobile broadcast carrying a mobile service that includesthe mobile service data and current and next (C/N) indicationinformation for indicating whether the FIC data are applicable to acurrent transmission frame or a next transmission frame; a multiplexingunit for multiplexing data in the data groups and main service data; anda transmitting unit for transmitting a transmission frame including themultiplexed data in the data groups and the main service data, whereinthe transmission frame comprises sub-frames, wherein each of thesub-frames comprises slots that are time periods for multiplexing themobile service data and the main service data, wherein each of the datagroups is transmitted during each of the slots, wherein transmissionparameters are transmitted in each slot during which each data group istransmitted, and wherein the transmission parameters compriseinformation for indicating a sub-frame number that contains the slot andinformation for indicating a total number of data groups to betransmitted during one sub-frame of the transmission frame.
 8. Thebroadcast transmitter of claim 7, wherein the transmission parametersfurther comprise an ensemble identifier for identifying the ensemble. 9.The broadcast transmitter of claim 7, wherein the transmissionparameters further comprise an RS frame continuity counter for servingas a continuity indicator of the RS frames carried in the ensemble. 10.The broadcast transmitter of claim 7, wherein: the FIC data are dividedinto a plurality of FIC segment payloads; and each of the data groupsincludes an FIC segment comprising an FIC segment header including FICtype information and one of the plurality of FIC segment payloads. 11.The broadcast transmitter of claim 10, wherein the FIC segment headerfurther includes an error indicator field indicating whether an error isdetected in the FIC segment.
 12. The broadcast transmitter of claim 7,wherein: at least two of the known data sequences are spaced 16 segmentsapart; and at least two of the known data sequences have differentlengths.